So, our ground floor walls are up, and ready for a concrete pour... almost! Despite our use of Logix ICF blocks, I had fallen in love with the simplicity of the joist hangers used by NUDURA. Essentially, all you do is slot metal plates through slits in the ICF blocks, hook them onto a bit of rebar in the wall, and pour the concrete. Then you wrap the end of your joists in a folded metal U-plate, and put tek-screws through the metal plates, through the U plate and into the joist. The shear strength of the metal plates and the tek-screws is what holds the joists up. So, before the pour, you end up with this:
Some people choose to put battens under the joist hanger plates before the pour to stop them moving during. We didn't bother, because the steel rebar was holding them fairly well anyway, although most of them were also screwed to the blocks (we'd finagled the joist spacing to fit the stupid imperial measurements of the Logix blocks, which meant at least one plate for each joist was able to be screwed to a web in the ICF.
So, the pour was uneventful in the end, apart from one tiny issue. Under that lovely 45-degree wall at the back of the garage, the block and beam floor was running under the angled wall. Which should be fine, but there must have been a small gap between the blocks somehow. After about 5 minutes of pouring concrete into the internal wall, we were getting a bit confused as to why the concrete level wasn't rising...
... It transpired that a 7N concrete block was now floating inside the wall, and the concrete was pouring through the resulting gap and under the block & beam floor in the garage, filling the void beneath. 🤬 We only realised how far it had flowed under the garage when we started lifting floor blocks. In total, in those 5 minutes, we'd poured just under 3m3 of concrete into the void beneath the garage floor - the void had reduced from an average 750mm height to under 150mm in places! On the plus side, at least it didn't fill the void completely, given we still have to run services under there!
Here's a photo showing how much it filled up:
Still, the garage walls aren't going to shift anywhere now! And it only cost £300 in spilt concrete...
Anyway, the rest of the pour went really well - no big bows (that we could see) and no bursts, despite all of the silly joints we had. Even little bits of PU foam seemed to withhold the weight of the concrete:
(No, the string isn't supposed to be tight to the blocks - it was set so that a piece of CLS fit perfectly behind. And yes, that upright should have been screwed to the ICF blocks... except the observant among you will have noticed the webs don't line up between the courses. This was a deliberate decision made by me because of an alignment problem with the joist hangers above the bifold opening, and this seemed to fix it)
So, concrete poured, and walls looking good:
The internal walls (garage, kitchen and stairwell) were kept 1 course lower so that they could act as a bearing surface for our upstairs floor joists. Seemed like a good idea to me, anyway!
Time for another ICF delivery...
The big RSJ is for the 6m span between kitchen wall and garage wall, and will carry the load of the first floor joists in the middle 1/3 of the house. All well and good, but the massive trees at the front meant that getting a crane on site wasn't going to happen, and the cost of a crane that could clear the trees from the street was more than a little prohibitive... Time for some back-breaking lifting, because that beam weighs more than 1/4 of a tonne!
Some swearing, and the death of a couple of ratchet straps, and the beam was lifted up into place...
And the length was perfect - we had less than 10mm tolerance once you allow for the required bearing on the concrete walls! Timbers sailed past the end at the garage - I was too lazy to cut them at the time (and that came laziness back to bite me on the ar$e later in the build!)
Say hello to the front of the house! Hallway window, nice doorway and the integral garage all present and correct
Before we can carry on building the walls, we need to put the floor joists up and get a floor deck down:
And time to start boarding it out:
Which would have been easy if it weren't for the fact that the tolerances on the board joints wasn't so woeful:
These boards were in the same pack, and the tongues varied by over 3mm. Biggest tongue we found across the lot was 20mm, and the smallest was 12mm. This meant we had to try mix-and-match for the floorboards, which took days longer than it should have... 🤬
Nevertheless, 7 days later, and we had the floor down, and were building walls again. 3 more days, and we were cooking on gas - first floor walls were 2/3 up and we were erecting the bracing again:
Time to put some lintels in for the windows (you can see the ICF cavity closer under the rebar links):
It was at this point that we realised we had a bit of a problem... our house was too tall! Our planning permission showed a street scene, which had the ridge line of our house lower than next door's house. The drawing had been produced by asking the neighbour to measure the height of his eaves when he was clearing out a gutter - he'd used a tape measure, so I had no reason to doubt his figures...
...But we were out by nearly 600mm on the height. I had to go back one night, and put a laser on a staff, just to see how bad it was. Here's the picture, showing the laser line from the top of a 2.4m staff, shining on the neighbour's chimney:
The upshot of this was a third planning application, and lots of sleepless nights, because we had to get a height increase approved (we first tried to use a minor non-material amendment, only to be told by the LPA Planning Services Manager that "a minor non-material amendment was not appropriate for securing an increase in height"... only to find out that the same Planning Services Manager had personally approved an increase in height on Chorley Nissan's planning application using a MNMA only 10 months prior! I wonder who had a nice Christmas present from Chorley Nissan that year?)
Still, while we waited for approval (so that we could order the roof trusses) we could crack on with bracing up the first floor openings. And we had a ground floor that was giving us a sense of what it'd be like when it was finished:
We were old hands at bracing openings now, having done it for the previous 2 floors of the house!
Anyone else think it looks like something from an early 80s arcade game?
Right, Christmas came and went - I had spent enough time with my family and friends, recovering from the previous 3 months. It was time to resume on site! ☺️
So, first up - inspect what the basement looked like, now that it was largely enclosed... Big mistake, because it was horrendous:
You can see that the water level is approx 2/3 of the way up the first course of blocks, so about 250mm deep. You can also see the bit of EPS that were chipped away to make the 95mm bearing surface for the floor beams, just floating around. Still, nothing that couldn't be remedied, and at least the basement was holding water - that suggested it might be able to keep the water out, too!
Now, we were starting to do things that required real tools to be kept on site. When the groundworkers were on site, we had hired a proper site cabin - hot and cold water, cooking facilities, drying room, toilet, etc etc etc. However, now that we were above ground, it was going to be just me and the occasional mate helping out. Kim had off-hired the site cabin, and swapped it for a porta-loo. Can't really keep much in the way of tools in a porta-loo if you don't want them nicked... So we decided to buy a van!
It had a few dents, but it was nice enough, and it would hold the tools, generator, etc, safely overnight. Cha-ching!
Now, another reason we hadn't made much progress over the holidays was because we were lacking some fairly necessary items to carry on building - the wall blocks. The ground floor ICF blocks were due for delivery the week commencing 11th December 2017. They actually arrived on site on the 12th January 2018, so just over 4 weeks late. This was something of a running theme with Logix, TBH... if you recall, the internal wall blocks for the basement were a few weeks late too (and you'll find out just how late the rest of the blocks were delivered later in the blog!) Still, they turned up eventually:
Still, ICF blocks now on site, we were able to progress... A day later, and we were looking at a decent amount of the external walls done (3 courses, most of the way around), and we were starting on the exciting 45-degree wall between the hallway and the garage:
3 courses turned into 4 courses, and all of the window openings started to be formed:
(The ladder was our only means of getting into the basement now, but TBH we didn't really care about down there - we just wanted to get the shell completed and progress to watertight as quickly as possible... Regrettably, that was going to be more problematic than anyone could have envisaged at this time!)
Anyway, the walls were flying up, even with all the steel reinforcement having to be put in. At least above-ground we only had a single face of steel to worry about (and our builder-turned-consultant pointed out that we didn't really need any steel at all except in lintels, because:
the concrete mix we were using was so strong, and
because you don't put steel into brick / block walls, which are perfectly acceptable for building houses with
But we did it anyway, just in case we ever decided to move the entire house to Jupiter (where 300mph winds area apparently possible, and where, therefore, our level of reinforcement would come in handy). 🤔
(In case you are wondering, the vertical steel isn't in as of this picture - they were all placed once the ICF walls were finished being assembled!)
4 more days on site (although 2 weeks had passed - remembering that I was only part-time at site, and I only had a mate helping me out on weekends), and we were putting up the bracing system again. Here's our exciting 45-degree wall inside the garage:
Isn't it lovely? You can also see the fantabulous set of steps I made from a couple of the many many 10" core ICF blocks we had left over, thanks to a considerable over-estimation by Logix. (I needed the steps anyway, because I am a short-arse and couldn't reach to put steel in above 3 courses!)
Some more pictures of the ICF going up:
Another week passed... And here, at the end of January 2018 is where it got... hmm, let's say interesting... it was time to put in the lintel blocks for the 6m bifolds in the kitchen...
It took me 3 days (so 2 weeks in calendar time) to get those blocks up and to sit square, and there was no way on earth they were going to stay like that with all the steel in them... time for some supports to be introduced to the opening!
Size 1 acrows every 1m across the opening. They're bearing off the concrete wall below, so no problem taking the weight. We put a single 250x38mm timber across the entire 6m opening, with 11mm OSB cut to 330mm rips on top of that (to support the ICF blocks fully). On the inside, the bracing system stopped the OSB from moving. On the outside, we screwed timbers down from the webs to trap it. Then we jacked up the acrows approx 10mm at a time until everything was perfectly level / square / plumb.
For some curious reason, I don't have photos of the steelwork in this wall, but it was prodigious - 2x25mm steel rebar in the bottom of the bottom course of blocks, 2x 12mm steel rebar in the top of the bottom course of blocks, and 2x20mm steel rebar in the top of the top course of blocks. 8mm rebar links every 200mm across the entire opening, plus onto the columns. I lifted and placed nearly all that rebar on my own (because my mate Paul had some family event on, he missed one Saturday, and I figured I could handle it)... big mistake! 7.5m lengths of 25mm rebar are very very unwieldy! I trashed one ICF corner block just resting the first 25mm bar on it while I got up on the scaffolding! Still, 5 hours of sweating and swearing later, plus some help from a more glamorous assistant in the form of Kim, and it was done...just in time for Paul to arrive and see how I'd gotten on! 🤬
Now, for the most part, the ICF walls had gone up fine. Even the 45-degree wall was a doddle. But those of you who were following the basement wall pour will probably remember that we had a couple of places where the basement walls went a little wobbly. This caused us a bit of a headache, because blocks wouldn't sit down properly in those areas. As it turned out, there was also an issue with the blocks not being level in those places either. This led to ever-increasing gaps between joints as we went up above those points, as you can see here:
Solving this was quite a problem. We ended up using about half a can of PU foam in the 3 places this had happened, followed by some serious strapping across both faces of the wall to keep it together. I spent several weeks trying to get everything braced (making bucks for the window and door openings), and plumb, and before I knew what had happened, it was the end of March 2018, and time for another concrete pour...
Stay tuned for the next exciting instalment!
And Christmas is a time for reflection, mostly because it was cold and wet and nobody would go to site with me to work! So, in addition to planning some stuff in my head for the upcoming few weeks, I took the opportunity to review the budget...
... And promptly started to cry.
We had budgeted £22k for groundworks, based on the estimate from the company doing the works. We had agreed to pay them on a day rate, with 6% overage for the foreman they were supplying - I thought that was a good deal.
At the point of completion of the block & beam floor, we had spent £40,231.28 on payments to the groundworks company, and a total of £58,085.79 including materials (backfill stone, concrete, steel rebar, heave protection, etc etc). So, before even laying the first above ground wall block, we were over budget to the tune of £36k...
The projected build cost was £250k in total, with a contingency of £25k. So we now had to find a way to reduce the remaining expenditure by £11k, or the build wasn't going to be finished.
No pressure then! 😬
It was at this point that I started looking at cheaper windows (since we had £20k in the budget for them) and internal joinery (Kim wanted oak everything but that was clearly not going to happen now). Oh well, Howden's finest for us then! 🙄
I am not sure what the lesson here is... Maybe don't build a basement?
Wot, no pictures? Nothing happened on site for nearly a week, so no (I thought about a gratuitous picture of me in a paper hat, but someone would probably come out with a quip about site safety).
If you want pictures, just wait for the next instalment - walls!
First off - an apology. I've been lax in getting this next instalment posted. Several days away over the holiday season led to several days more trying to sort out family issues, which have since spiralled out of all proportion. I think I have now put the genie back in the bottle, so on with the show.
Where were we? Ah yes, we'd poured the basement walls. They'd gone a little wonky (because I was a numpty and failed to install adequate bracing on the outside of internal T-walls), but we had walls that we could build up from.
Time for backfill and construction of the remaining foundations (our basement is only 60% of the width of the above-ground house). Before that, we needed to fit a drainage channel around the basement walls & slab. Here's the groundworkers putting the (terram-wrapped) french drain in around the slab/wall junction, which was then covered in 10mm pea gravel to a depth of 500mm, and then 40mm clean limestone:
This actually led to one of the most enduring memories of the project to date. I was laying the drain outside the far corner of the basement (where the cave-in nearly smashed the wall apart). The groundworkers had decided that they wouldn't get in that part of the excavation (between the concrete walls and the bank) in case of further cave-ins, so myself and a couple of mates sorted out the drainage channel. Unfortunately, it had rained a lot over the weekend, and was muddy and slippy and wet... Standing on the edge of the slab was precarious to say the least, and I'm not the most svelte individual... Long story short, I fell into the mud. Which sounds funny, but at the time, it was rather terrifying, because of the depth of said mud, and how much effort it took to get me out of the mud.
Don't believe me? Here's how deep it was:
Took 2 people to lift me out of the mud, and I came out without one of my boots as well, which has never been seen since. I had to walk home, because I didn't have a change of clothes, and I had come to site in the Jag. So over an hour, with outside temps being about 3C, trudging home feeling very sorry for myself. At least my mate lent me a pair of boots!
One detail I haven't mentioned prior... The basement walls are 10" thick concrete core, but the above-ground walls were designed to be 6.25" concrete core. The mathematically-astute among you will have already worked out that gives 3.75" (or a touch over 95mm in new money). This was intentional, because I figured I was a clever so-and-so, and could use that 95mm as a bearing surface for concrete floor beams. Genius, eh?
Well, maybe. It did give us a nice bearing surface, and it did remove a potential cold join between pours at ground level, so big win there. However it then entailed removal of a large amount of EPS from the inside of the blocks so that the beams would slide along on this concrete (because a crane wouldn't get on site very easily, so we used manual labour to move the beams), so the labour aspect was considerable. It took better part of 2 days to remove the EPS (and resulted in about 3 builders bags worth of EPS fragments sitting in our basement), and another 2 days to set the beams in place and start laying the infill blocks.
Here are the beams going on:
And here are the floor blocks being laid:
Here you can see the EPS having been removed en mass from where the beams had to slide. Don't worry - it's not a giant thermal bridge, because
we put EPS back around the beams once they were in situ properly (albeit much later in this story)
we have now put insulation above the floor beams for the UFH to sit on top of, and
we will shortly be putting insulation under the floor beams in the basement ceilings too (cos we have a load left over)
(The big hole is where the stairwell is going, in case you're wondering!)
We backfilled at the same time as laying the floor beams. More precisely, because of a battle of wills between the engineer and the groundworkers, we backfilled to approx 50% of depth, then laid the beams (with the walls evenly loaded all round by the backfill to "prevent asymmetric destabilisation and collapse") and finally finished the backfill. 440 tonnes of backfill went in around the basement - that's a lot of stone!
Next up was the remaining foundations. Building Control had specified a minimum depth for the mass-fill RC footings for the rest of the house, because of the massive lombardy poplar trees at the front of site. A nice big strip was dug out (2.5m deep at the front, and 1.5m deep at the back of the plot - furthest from the trees), and filled with concrete.
The engineer had specified cages of 16mm rebar to make our ground beams that linked the mass-fill footings to the basement walls, with clay heave protection, so we dug out from the clay capping over the backfill, formed shutters with the heave protection, and dropped in our cages:
Once the concrete had started to cure in earnest, we laid the first course of blocks on the new foundations, and linked into the basement wall blocks. The steel reinforcement is probably overkill, but better safe than sorry when your engineers starts saying "you don't want the two halves of the house to separate"...
The blue pipes were my attempt to ventilate under the block & beam floor that we were going to lay over the new foundations. Turns out that Building Control didn't care a jot about that once they saw how much backfill stone we had placed - not sure why that would matter, but there you go! Concrete was poured in this course of blocks to stabilise everything, and get us ready to carry on with the build.
Myself and a couple of mates laid the remaining floor beams in a weekend:
That'll do for now - as my Mum used to say: "keep 'em wanting more!"
Before I carry on, let's answer the question I posed in the last blog entry. I posted this picture of the basement rear wall, showing how we had joined the cross wall to the side wall (following the suggestion of the boss of Logix UK, who had attended site whilst the walls were being assembled (and even assembled some of them himself) as part of our on-site training:
The problem here is that this wall is supposed to form part of the watertight barrier of the basement. The concrete had to be continuous. But of course, with this design it wasn't continuous - we only had pockets of concrete, 5" deep, every 16" up the wall. Structurally, it was more than up to the job. From a watertightness perspective, it was about as useful as a chocolate teapot.
But we didn't even think about this until much, much later. About 6 months after the concrete pour for the basement walls, in fact. By which time, remedial action became very complicated and very expensive.
Let's return to the blog timeline...
So, basement walls were constructed in about 8 elapsed days, which amounted to 5.5 days on-site. I was suitably impressed. 2 faces of steel rebar was set into the external walls, at 200mm centres vertically and horizontally. This was at the behest of our waterproofing specialist, who had overruled the SE. From a structural perspective, the SE had calculated that a single face of H12 rebar at 200mm centres was more than adequate to reinforce our 10" thick concrete walls and withhold the ground pressure. Our waterproofing guy said "the more steel the better, because it'll control the cracking better". So, with the steel not actually being that expensive, we ordered double the steel, and put 2 faces in.
Thank goodness we did. Remember the bank at the back that was propped on 4 acrows? They were rated at 1 tonne each. 3 days before the concrete pour, they failed overnight. A shelf of clay, weighing perhaps 6 tonnes, forced one of the acrows to deflect enough to destabilise the lot, and the shelf gave way, slid down the back of the excavation, and smashed into the polystyrene wall.
Unbelievably, the wall, supported by the ICF bracing system, held. Here's a photo of the damage:
The bracing upright was bent to the tune of 10 degrees or so, and most of the studs that interlock the ICF blocks had sheared off. But because of that 2nd face of steel rebar, the wall resisted the impact, and the subsequent dead weight, of the clay against it. It took 2 hours and a few extra steel supports, but we managed to force the blocks back together, and brace it up sufficiently that it would take the concrete pour.
And a 3 days later, that's what we did. The concrete pour was moderately uneventful, as these things go.
Apart from the pump getting blocked, because a piece of hardened concrete had made it into the mix in the batching plant, and then completely blocked the 3" reducer we were using:
It took nearly an hour to dismantle the pump, knock that lump of concrete out, and reassemble the pump. The concrete firm said they'd have to charge us for the concrete wagon sitting outside doing nothing. I replied that was fine, but they were picking up the tab for the pump since they'd blocked it. They said for me not to worry, and apologised for any delays they had caused...
Oh, and one more problem - where the T-walls had been made, I hadn't braced the outside of the side walls sufficiently (or at all, truth be told!). This led to some substantial bulging of the side wall in a couple of places, which I had to shore up as a bit of an emergency 😟 The concrete was poured, and the walls started to harden pretty much as soon as it was poured. Here's the bulging:
Ahem. Nothing to see here, move along. 😭
At least the shoring / bracing held.
So, our slab is down, starter bars set ready for our walls, lovely. Time for some ICF...
Nope - more prep work to do first, apparently. The boss from Logix UK came up a couple of weeks prior and gave us some on-site training. "It's just like Lego!", exclaimed I. To be fair, it did seem really simple. I learnt just enough on the first day of training to be dangerous.
The basement wall blocks arrived on a pallet truck. Except it was only some of the blocks - they'd forgotten to send the internal wall blocks, and only sent flat panels for us to make most of the blocks ourselves. No biggie - it only took a hammer and 60 seconds of effort to assemble each of the blocks. Shame there were a couple of hundred...
So, getting the blocks into our hole was entertaining, though - we started off hand-balling them down a ladder! After we had a few down, we started looking to set the first course. We bolted a set of aluminium track around the perimeter - the track is 72mm outer width and 70mm inner width, which is exactly the same width as the EPS panels for the basement. It came in 3m lengths, so with 16 lengths bolted down, we had a perfect perimeter into which the blocks would sit.
Here's the first block going in for a trial fit:
Oh, the sharper-eyed among you may have noticed there is what looks like a channel/groove set into the slab, just outside of the starter bars. That was cast into the slab (using lengths of 20mm electrical ducting) to take the Sika swellable water-stop bar, and it was a perfect fit... shame we didn't think to set it into the channel until after we had placed the first course of blocks! DOH!
Anyway, the block fit perfectly, so we carried on setting out the entire first course, then realised our mistake and put the swellable bar into its channel (stuck down with some horrendous swellable mastic provided by Sika, that took best part of a week to wash off my hands - oops!)
So far, so good. But hand-balling blocks or panels down a ladder wasn't cutting it, given we needed to get several hundred blocks down... so we made a slide! The pairs of timbers were set so that the webs on individual panels fit perfectly between the 2 timbers, keeping them level and preventing them from flying off.
Before we knew it, a good chunk of the basement walls were up. Next day, and we continued apace. By the end of the week, most of the basement walls were up and it was time to call it a day. The man from Logix had suggested we cover the tops of the walls temporarily to prevent the swellable bar from getting too wet, so we used the ICF cavity closers - after all, we were relatively sheltered from the wind, so they shouldn't go anywhere...
Next day onsite was the following week, and a surprise arrived - the internal wall blocks! Not only that, but the boss of Logix UK arrived with them, to carry on our on-site training...
Since he had brought his internal wall blocks and the bracing system with him, I figured he could help with the internal walls. Now, if ever there was a mistake...
I don't know if anyone paid attention to the design of the house, but there is this lightwell out the back of the basement. It's designed to serve 3 purposes:
To provide a secondary means of escape, in case the basement stairs are on fire (there's a window being put into the back wall)
To provide a place to put the rainwater harvesting tank (I'm a notorious cheapskate, and I had noticed that above-ground tanks cost a fraction of the below-ground tanks... ergo, with a lightwell - covered by a deck at ground level - I could house a giant above-ground tank, but keep it out of sight!
To provide somewhere to site our perimeter drainage sump (we were going to backfill around the basement walls, with a french drain that flowed into the sump chamber in the lightwell, so that it could be pumped away, and remove hydrostatic pressure from the basement walls
"So why is he banging on about the lightwell?" I hear you ask. Good question.
Internal T-walls with Logix are made with dedicated T-shaped blocks...in the US and Canada. Over in Blighty, they're not allowed to make those blocks (because Logix UK is a licensing outfit, with very limited production rights), so you have a choice of waiting up to 6 weeks for them to be shipped across the Atlantic, or bodge the T-wall by simply cutting pockets out of the side walls to allow concrete to flow between side and cross walls, and you can put rebar L bars into the wall to tie it all together. Which option do you think I picked?
If you look carefully, you can see the pockets cut out of the side walls, and the steel rebar hanging out of the side wall to tie the side and cross walls together.
Which would be fine, except this is the external wall of the house. The area to the left of that wall is the basement, and the area to the right of that wall is the lightwell.
Now here's a little test for the brighter students among you... what's wrong with this arrangement? Answer in the next blog post! 🤬
Ok, so maybe I got a bit ahead of myself again...
The second wagon that they filled with spoil didn't fare as well. Matter of fact, it managed to beach itself on every axle:
The muck-away company had to send a 2nd wagon, fully loaded with 6F2 and a big-arsed chain. Then it dragged the beached wagon out across the street using the chain. The (now-freed) wagon drove off with our load of spoil. Since there was a load of crusher run on the rescue bus, we had it tipped on the front of the plot, to stabilise the ground and prevent a recurrence.
So, excavation continued apace for the next few days. Apart from a few more land drains excavated (including an abandoned rat nest), things went well. Here's a few more pics for your delectation:
We decided on a stepped bank initially, to try and prevent bank collapse:
But as this photo shows, we were still fighting the effects of the bad weather - some small cave-ins, and we started adding acrows to shore up parts of the banks:
Now, when we started investigating the options for basement excavation, we had previously considered sheet piling the excavation. However the 2 quotes we received both sad that the steel sheets would need to be left in the ground ("sacrificial" was the word used) because the sheets wouldn't be able to be extracted. And with quotes coming in at over £60k for the sheet-piled excavation, it was well over our budget.
So when the groundworkers told me that the excavator was starting to fall into the excavation, and we needed to sheet-pile the front of the hole, I was more than a little concerned. Still, it appeared to work:
So the hole was finished - only 74 wagons of spoil taken away... Concrete blinding was laid oversite to stabilise the clay underfoot, and the shuttering for the slab constructed. Then the mesh and starter bars were set into place, and we were ready for the slab to be poured:
And lo, our first concrete pour arrived - the first of many!
And before I knew what was happening, the slab was done (notice the increase in the number of props / acrows):
Time for some ICF...
Our groundworkers broke ground on October 9th 2017. Here's the digger and fuel bowser arriving:
Bit of a squeeze, but they got it on-site in the end! The driver set to work on the site strip right away. He'd been working for perhaps 45 minutes, when work ground to a halt... A land drain was exposed (well, kind of dug up, if truth be told), in the middle of the plot, all of 6" below the ground. The digger had removed a 2' section of it completely, as this photo shows nicely:
Oh well, can't have been that important! 😁
So the scrape is completed, with vegetation separated off from topsoil. Here's our mountain of topsoil (about 20m3), ready for when we want to spread it back over our garden (and me, feeling all smug about the progress we're making in the space of a day!)
And the vegetation... well that was loaded by the excavator onto a 32T wagon. Now we had already arranged for pre-acceptance of our clay spoil at a quarry/landfill about 2 miles away, so the driver says "it'll be fine". 30 minutes later, the driver is on the phone, saying "I'm trying somewhere else - they wouldn't take it here". Another 40 minutes, and another call... "I am off to another place"...and so on.
So roughly 4 hours later, the wagon arrives back at site. Still full of the vegetation. "Nowhere will take it", says the driver. "It's because of the roots in the load", says the driver. Turns out, the driver has given my vegetation a tour of the North West, having been to 3 separate counties with it. I'm fairly sure he just took a fancy to it, and they went on a drive in the country... he probably bought it a cream tea in Blackpool and asked it back to his place... Here's the wagon in question:
Still, could have been worse... the groundworkers pulled a magic trick out of their hat. They dug a Transit-sized hole out of the bottom of the plot, and dropped the vegetation into the hole. Then they loaded the spoil dug out of the hole onto the wagon, and that was accepted at the quarry. The groundworkers compacted the vegetation, put a 600mm capping layer of clay over, and job done.
Pretty successful day, if you ask me!
Waiting isn't something I am known for. Waiting nearly 3 months, for these mythical birds to vacate the invisible nest isn't going to happen.
4 weeks later and we're into July, and I've had enough. Here's what was left of the hedgerow, along with my weapon du jour.
As it happens, there was no nest in the hedgerow. Probably because the houses all around have cats that hunt, and even birds aren't stupid enough to nest 4 feet off the ground when there are dozens of suitable nesting places in the trees on both sides of the street! The closest thing I found to a nest was a 20-year-old gin bottle, filled with cobwebs. We also chopped down about 50m2 of brambles and a few western red cedar that were in the middle of the plot. Then we put a bit of Heras-style fencing around. So now, our site looked a lot cleaner and larger:
But we had still waited too long. The firm we had verbally accepted a quote for the groundworks from had moved onto a large new job, and wouldn't be able to return to our project until the new year. 🤬
Time to find some new groundworkers... should be simple enough, right? Wrong. A big contractor had just pulled out of a major development project a few miles away, so every groundworks company within 20 miles had been signed up to take up the slack. We looked at everyone from "one man with a digger" to big national outfits, but nobody was able to take the job on. Until we found this company, based in Liverpool. Smallish outfit of about 15 men and a couple of decent-sized machines, including a shiny new 13 tonne excavator. After some to-ing and fro-ing, we decided to take them on, on a day rate basis.
Planning passed (way after the expected date, but that's nothing new with our LPA apparently) - both applications. So Kim chose the big kitchen layout. But before we could break ground, we needed structural calcs done, and that meant an engineer!
After ringing around quite a bit, we found a local firm that were happy to take the job on. They didn't have much ICF experience, but I figured that it wouldn't really matter. How wrong I was...
This engineer started off on the right track, working out slab details from the borehole results, etc, etc. Then it came to the ICF lintel and column calculations. Now, the new kitchen design incorporated some 6m-wide bifold doors across the back of the house, with 1m-wide columns either side of the bifolds. We had picked Logix as our ICF product of choice (primarily price driven, but also because we could have thicker external wall insulation, which would improve our thermal performance considerably).
The Logix blocks were 406mm high, and had plastic webs for supporting horizontal rebar at roughly 1/4 and 3/4 of the height of the block. Here's a pic:
So far so good. Except our engineer had decided that the steel would be placed every 150mm vertically in the wall for the columns either side of the bifolds. Now, for the layperson, I'll point out why that doesn't work. Here's the list of positions for the steel vertically, in mm:
- 150, 300, 450, 600, 750, 900, 1050, 1200, 1350, 1500, 1650, 1800, 1950, 2100, 2250, 2400, 2550, 2700
Now here are the positions where the rebar is supposed to sit:
- 100, 303, 506, 709, 912, 1115, 1318, 1521, 1724, 1927, 2130, 2333, 2536, 2739
Notice the numbers in BOLD in both lists? That's where the web would physically get in the way of the steel rebar. Cutting the webs would destroy their structural integrity completely, and mean you have to find alternative ways of bracing the ICF wall blocks - which would be possible if they weren't corner blocks. Which they were.
I pointed this out to the SE. He said I didn't know what I was talking about. So I had my ICF expert builder (who agreed with me about not cutting those webs) come and chat with the SE, and explain the same thing. The SE smiled, and said that it would be fine. So I had the ICF block manufacturers (who also agreed with me about not cutting those webs) ring and email the SE.
The next thing I know, the SE has emailed me, saying (and I quote, here);
The fact that we couldn't use his designs, because they were inherently unworkable, was the problem in the first place!
Lesson learned - do NOT engage a structural engineer who doesn't have experience with ICF when you're building an ICF house. 8 weeks we had been working with this engineer, and all for nowt.
Phoned a couple of ICF manufacturers for recommendations for an SE with ICF experience - there was 1 common name on the 2 lists I received back. I phoned him, and accepted his quote the same day. 4 days (not weeks) later, I had the calcs in my Inbox, and an invoice to be paid. The steel was in the right places for the blocks we were using, and we even had little detailed drawings showing how to tie the lintel links to the main rebar, and where we had to put what types of welds & bolts to bring everything together properly.
Maybe our fortune was changing for the better at last...?
Preparing the documents for the planning application was simple enough. We paid a nice man to come and prepare an "arboricultural impact assessment". Basically, he looked at what trees were on and around site, asked which we'd like to keep, and went away. 3 days later a nice 22 page report appeared, and remarkably it said good things about only the trees we had expressed fondness for.
Then another nice man came around and dug very narrow, but very deep holes in a few places on site. Here's a photo of his contraption:
The boreholes only went down just over 6m, because we were having a basement rather than a well. Still we got fairly good results - the clay was stupendously stiff. At one point we had the borehole man (who didn't want his photo taken) and myself hanging off the lever arm, trying to withdraw the thing from the ground! 🤣
So, we submitted our application. Job done, I thought.
A week came and went, and we had a nice sunny day, so the missus and I thought "let's just peg out the layout of the rooms on the plot, and walk around it". Genius. We bought a builder's line and a stack of short bamboo canes and went to site. I spent about an hour pegging out the dimensions of each room on the ground floor layout, and thought it looked fantastic.
"It isn't big enough", says Kim. Now I know where your imagination is going here 😈 but she was talking about the kitchen.
Back to the drawing board, and about another week elapses. I redraw the house from top to bottom, and now we have a kitchen that is 30' wide and 16' deep. New plans submitted, but we keep the original planning application in the process, just in case...
Things went from bad to worse... The Trees Officer for the Council came around, and said "the Tree Impact Assessment is fine, but you can't get on-site now until August". Puzzled, I enquired as to why. He pointed to the hedge:
"There's birds nesting in there - I can see a nest! You'll have to wait until August to cut the hedgerow down for access". 🤬
So, we've lost some time with solicitors losing paperwork and being generally unable to handle negotiations where there are more than 2 parties involved. We've lost more time, having to submit a second set of plans because Kim thought the kitchen was too small. We've lost our builder because of the delays. And now we can't get on site for 3 months anyway (other than a tiny pedestrian access), because the front of the plot is blocked by a hedgerow... All the while, we're paying our self-build mortgage.
Can things get any worse?
But I am getting ahead of myself here...
Whilst the purchase was ongoing, I was assuming a number of roles in the project. One of which was the "architect" (and yes I know I am not an architect, and not allowed to call myself such, hence the quotemarks).
So, I bought a piece of house design software and spent a week playing. I came up with what I thought would do nicely... a big box with a pointy lid and some windows (and doors).
On paper at least it ticked all the boxes, and fixed all the problems we had with our present house (poor flow, not enough space, the usual reasons people dislike their present house and want to move).
So, having designed a house, we submitted a planning application for it (the plot only had outline permission). I spoke to a planning officer and was told the sort of things they wanted to see. That included:
- a full EPC calc for "as designed" and "as built"
- borehole records because there might have been shallow mine works under the plot at some time in the past
- an arboricultural study because we were going to have to cut down a few wonky goat willows that sat close enough to the build area to be a problem
We did all that, at a not insignificant cost, and bundled it with my designs for the house, shown here for your amusement...
Clancutt Lodge - Floor Plans - CL_FLOOR_01A.pdf
Kim and I were/are avid watchers (and readers) of Grand Designs, and so we took the plunge - we would build our own house.
Well, sort of. Our plan was to "armchair self-build". I would design the house (big box with a pointy lid and some windows and doors), and we would get a builder to construct it. Seriously, at the point we were buying the plot, that's as much as we knew had to be done. Of course there was the detail, but we expected the builder to handle most of that - after all, that's what builders do, right?
Wrong. But by the time we sussed that out, much time had passed and we owned the plot. And by "much time", we are talking many many months. Here's why...
First, because the house and plot were on the same deed, we had to arrange for them to be split. That led to negotiations between 3 sets of solicitors.
Then my wife and I decided we would have a basement. That led to Party wall negotiations, because we were going below the zone of influence for the neighbouring foundations (just).
During all this, we had visited a number of self build trade shows (Harrogate, Swindon, Manchester, etc) and had settled on ICF as the way to go. So we found ourselves a highly recommended ICF specialist builder who agreed to build our house for us - splendid.
But by the time we had completed the purchase of the plot, nearly 6 months had elapsed, and our builder had moved on to other work. To his infinite credit, he offered to consult on our build for free, but we would have to build it ourselves...
... Now I am a software engineer and project manager by trade, so I had already decided I would manage the build... and how hard could it be, building an ICF house? After all, I am good with Lego - here's proof!
I am Neil, and this is the story of my self build - warts and all.
First, some background. My wife and 2 girls and I live in Lancashire, in a 5 bed detached modern build house on a smallish estate. For a few years, we have looked around for somewhere a bit bigger, but in the same village. We had no luck for ages - everything was either too expensive, or too small, or too near a busy main road (and frequently all 3).
Then in December 2016, a house with a large garden came on the market only 4 streets away. Perfect location, and it needed a load of work doing to it, so it was going cheap. We went to have a look.
House was perfect for what we needed. Ok, so it needed extending - it was 100m2 of floor and we were thinking of making it more like 250m2... but the garden was easily big enough to make that viable, and we had the budget to do it. Better yet, there was a plot of land for sale (with outline planning permission) which used to be the side garden for the house. We put in offers for both of them at the asking prices...
So did several dozen other people. It went to sealed bids, so we offered 17k over asking for the house and 15k over asking for the plot.
We got the plot but NOT the house. Hmmm, what to do?
Here's the plot and the side door of the house - it doesn't look much, but both sides go back another 25m behind those trees... total of approx 600m2, and a snip at £100k plus fees for the plot...