Spinny

My thoughts are generally to build what the architect specified so that in the event of any future problem, you can point the finger at them, and they don't have the ready made get out that you didn't build what they specified. Any changes have therefore been bought off with the architect first, and using Marmox blocks would need to go around that loop. (Unfortunately the original architect left the practice early in our build and so the senior partner had to take over but we were then charged £100/hr instead of £70/hr!) I have done various bits and pieces as has sometimes been unavoidable (protecting the works & keeping the rain out, removing lathe and plaster ceiling and hacking plaster off the walls, putting preservative on the joists, putting in conduit and cables under the floor, driving across the country in a hired van to collect a rooflight from a company in liquidation. etc). I live on site so have kept an eye on the works and been a kind of makeshift project manager, come tea maker, and 'that can't be right can it' person, and having to source, order and take delivery of anything that can't be bought off the shelf at any builders merchant from underfloor heating parts, to LED strip controllers and profile, to smart home modules, to aerogel, to roof straps. I am in my 60's now having been a young man when work began of course 🤪👴, so not up to much any more.

I don't think it is that unusual these days is it ? The frame needs to be fixed into something and the cavity is PIR insulation and a cavity closer, so they fix the frame to the inside edge of the outer block. Not ideal as there can be some thermal bridging through the block and round the thermal break in the alu frame (although they end up with packers and foam around the frame too). We used two different window suppliers and they both fit like that.

Thanks Russell. It was all a last minute thing as the water pipe was supposed to be moled down the driveway, but they couldn't do it as the mole just kept hitting rocks in the ground, so had to come back next day with a digger to trench it. I woke up at 5am thinking, hey I could use that trench to conduit a future fibre broadband cable under the driveway and directly into the side of the house where my network stuff lives. So when the workman returned I went hotfoot to buy something as they were already well behind on the job and eager to get finished. They needed to get the job all done, so have immediately laid new patches of concrete where they had to cut through. I might get a second chance to do something as and when I replace the concrete pad. I suppose another option might be digging the hole 3m outside to get back to the conduit, then attach some new conduit to it of the same OD and then using the existing conduit to pull the new conduit through the same hole, but could be dodgy, and where would I find a 25mm OD underground conduit. The one I used I see now is IP54 rated - presumably would take many years to degrade in the ground though ?

The trencher had one but it wouldn't pass far down either end - didn't seem as flexible as the cat 6 cable.

Thanks for all responses. Further investigation today by pushing cat 6 cable down the 25mm flexible conduit (bought from Toolstation) shows that cable can travel 6.3m down the conduit from the house end before it meets an obstruction and only 2m down the conduit from the far end. So I presume the conduit must have been crushed (or possibly bent ?) at these points, though the henry vacuum does produce significant suction from one end to the other (!?!). The only good news with this is that 6.3m from the house end is just beyond the concrete slab in front of the house. So in theory digging back down 750mm in that one spot should allow the conduit to be cut and joined to a new piece to travel the rest of the way. I guess this means I can reassemble the qtr landing at the bottom of the staircase, but maybe need to dig the hole first.

Had someone installing a new mains water pipe. They ended up having to trench it the 25m to the house and managed to break the old lead pipe in the process. As it was being trenched I thought I would get some 25mm flexible conduit down the same trench before they filled it in (to take a future internet fibre cable). Spent quite a while messing about with a drill bit attached to some cord to work the cord down the 25m of flexible conduit and secured it at each end with something to prevent it getting pulled back and lost in the conduit. But god didn't grace everyone with a brain and the trencher buried it then decided to cut the 'spare' off the end releasing the string back down the conduit. Expletives were uttered - just another episode in my cursed 2.5 year attempt to get a modest extension. A fish tape was tried but got stuck a few metres down the ribbed conduit. An attempt to suck down some string taped to a piece torn off a plastic bag with a Henry vacuum only slowly pulled it a few metres. I still have the original cord taped to one end but of course the other end is lost, so we thought we would pull this cord out and try the vacuum again, but hell now even the cord is somehow stuck in the conduit and will not pull out. Seems like I am s###### again - any ideas on how to try to get something down the conduit ? Trencher believed cable companies use sort of air gun to fire the cable down ?

New bifolds are top hung and fixed into a steel I-Beam across the opening in the outer leaf. So the edge of the steel is level with the face of the concrete blockwork, but there is a deeper web in the steel to be covered over. Architects drawing says fix a render board over the steel and then 'thin coat' render whatever that might be. Someone quoting has said fix render board over and then render over but the finished render will end up quite thick over the concrete blocks to match the render board. So rather than 20mm thick finished render, would end up about 32mm thick. I am not sure how this is going to look where the base of the render ends at DPC level - might look odd ? Is this usual way to do it, and what is the 'thin coat' render and is that a better answer ? (Also should something be used to infill the web of the steel, such as timber or insulation and how should this be fixed in place. I can see the possibility of wanting to drill and plug the wall for fixings - e.g. for an awning, camera, etc, so leaving the web open and hollow behind the render doesn't seem ideal)

Thank you Nick, I have never come across Marmox blocks before, an interesting alternative to celcon blocks which seem to be essentially reinforced XPS blocks. Not something my architect or my structural engineer ever mentioned. Problem is the bifold doors are installed by the bifold company (not local), and I have already had 4 install visits to get to this point with the bifolds finally installed and working properly.The concrete blocks under the threshold were originally celcon. It is a long story... When the builders poured the heated concrete slab they decided to 'tack mortar' the celcon blocks into place under the bifold opening. Their plan being to avoid having to cut all the blocks manually down to threshold level later in situ, because they would be able to remove them and machine cut them and re-lay them. However unknown for many many months (until the bifold fitters arrived) when they did this the blocks bowed forward under the weight of the poured concrete hence the rework to cut the front of the slab square again. In addition when they relaid the celcon blocks the bifold company found some to be loose. The builders tried to fix by re-laying them with 'quick setting mortar' but they still had movement 36 hrs later. The builder insisted the celcon blocks were the problem because they didn't take mortar well. The architect said any competent builder shouldn't have a problem, the structural engineer said sometimes they could suck moisture out of the mortar too fast and it was important to wet the blocks. I said I am not playing trial and error building at my expense when the bifold company are charging me money for every failed visit. In the end the architect agreed that concrete blocks could be used with XPS on the outside. The whole shebang ran over many months. We have since had to sack the builders after a negotiated settlement and are now 2.5 years into an extension project that was supposed to be done in 6 months. So unfortunately paying the bifold company to remove and refit the threshold (2 visits from 5 hours drive away), plus finding a competent builder to re-lay marmox blocks or anything else, plus paying more architect fees at £100 per/hr and more structural engineer fees to sign it off, plus waiting months to achieve this, just isn't a viable option anymore. It is also unknown whether the bifold company would guarantee a fitting onto marmox blocks as presumably any fixings have to be carefully positioned. I think I am stuck with either putting a layer of XPS on the outside down to an accessible depth (architects recommendation), or leaving it out(another visiting builders suggestion). So still interested in answers and thoughts on my questions above.

Yes you are reading it right. Photo attached. So would be putting 25mm XPS externally against the blockwork and it would end up below ground when the patio is made up to level with the threshold. I don't want to create a problem 10-20 years down the line by having it there or getting ants in it etc. Clearly there will be still be cold coming up into the blockwork under the bifold through the footings, but I guess the external XPS would inhibit losses out towards the ground under the patio which is nearer the surface and therefore gets colder in winter.

Just a thought, you could consider adding a smart switch module into the wiring to enable the LED to be controlled independently.

My rear extension has a 130mm concrete slab with heating pipes within, all connected up and functioning. The slab has 150mm PIR insulation under and 25mm PIR edge insulation around the perimeter just inside the blockwork walls. There is a 3.5m wide opening with bi-folds installed at one end and the inner leaf of the cavity wall was left out so the concrete slab runs out to the outer leaf of blockwork under the bifold. The bifold track is installed on this outer leaf of blockwork. The original specification had a course of celcon insulating blocks across the bottom of the opening and under the bifold track and a 25mm upstand of edge insulation inside this, then the concrete slab. However the builder had 'construction issues' and to resolve these it was eventually agreed to allow concrete blocks to be used instead of the celcon insulating blocks. Furthermore the front of the concrete slab and the course of blockwork was found to have a bowed outwards curve under the bifold opening when they came to fit the bifolds. To fix this the blockwork had to be removed and later relaid while the front bow on the concrete slab was cut off to straighten it up with a big circular cutter - this also led to some damage and reduction in the effective width of the 25mm edge insulation. So the designed insulation at the bifold opening was reduced from 25mm PIR + 100mm celotex block to 15-25mm PIR only. To provide some compensation for the loss of insulation the architect advised adding 25mm XPS insulation on the outer side of the concrete blockwork under the bifold. The ground level outside is going to be made up with hardcore and a patio to be level with the bifold track, so the XPS insulation will be underground when complete. I am in the UK at about the same latitude as London. My questions are: 1/ How long will this XPS insulation last in that position ? 2/ Am I best to add a cavity drain membrane over the XPS to help to keep it dry ? (or is there a waterproof coated XPS product out there) 3/ How do I adhere the XPS insulation to the concrete blocks ? 4/ Given the XPS insulation will be to a depth of 300mm (maybe 400mm) and this insulation will complicate the patio construction - will this give me a worthwhile heating benefit or should I just forget the XPS altogether ? many thanks...

I have two rainwater downpipes running down from extension roof to be connected into pipe runs to a soakaway. Both downpipes are located at internal corners on the outside of the building. I have been shown standard bottle gullies which provide a water trap but cleaning or access for rodding seems a problem. I also see there are alternative gullies for downpipes which have a leaf catcher built in and a removal cover to clean, however they do not have a water trap to stop odour - is this something I should worry about ? What do people usually do for downpipe gullies to a soakaway (I am putting a silt trap in at the soakaway) ?

May be posting this in the wrong section, but currently have lots of materials and other items which have been delivered but cannot be installed due to extremely long build delays. This is cluttering up the site and getting in the way. Can anybody recommend the best approach to storage problems ? There are self storage units, getting some form of storage on site, splitting the items up and storing in different places on and around site, purchasing a storage building/container of some sort etc. There will be items needing storage for many months yet. All getting like very hard work trying to research the best approach. Initial self storage provider enquiries are coming out around £450 a month for 250sqft which assuming up to 12 months storage is £5400 ! There appear to be absolutely no discounts for a committing to 12 months storage, or paying a year in advance. It is a lot of money to spend on something intangible. There are all manner of items you don't want getting wet or frosted etc. The site has a slightly sloping front area and only narrow access to the rear. Unsure if shipping container makes sense when unheated through the winter etc. Any advice ?

I’ll check, but it is 4 rads, 2 standard rads, one 3 column rad, one 2 column rad. Nothing bigger than 600 by 900. Plumber has been to rebalance them 3 times now. The last time he has been dishonest and turned up the boiler to 65 without telling me to try to escape the fact the rad pipework must be a problem.

Builders plumber started by saying the PRV could be a problem but he has now replaced it but it has made no difference. Gledhill PRV has been replaced with a Caleffi PRV. Plumber claimed the old PRV would be returned and tested for faults. But I never saw it as he must have whisked it out and hidden it in his van - perhaps he didn’t want me to see it wasn’t clogged. I rather doubt anyone is going to test a £30 part for faults! He also couldn’t get offsite fast enough.