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?