Warrentdo

Hello all, I've come to the conclusion that I don't want 21m/sq. UFH in my new extension. It was originally on the plans but I really don't think its worth it for a number of reasons. I will be replacing the UFH with a radiator. The issue that I have is that the base is already in (apart from the screed) so 200mm concrete then 150mm insulation then 65mm screed instead of now ideally the insulation under the 200mm concrete. I was also looking at replacing the screed with concrete as I have enough on site to finish. Does anyone see any issues that I will come up against?

Hello, I am looking for a little bit of advice before I get a plumber involved. I’m looking at adding 20mtrs underfloor heating to my property. I currently have a 15+ year old Vaillant ecotec-plus-937. My question is, is it worth upgrading the boiler to something newer that maybe more compatible with todays controllers and can modulate better, or does it not matter? I hear horror stories connecting old boilers to work with UFH (electronically) Any advice welcomed.

I've just remembered that I have 10 tubes of Soudaflex 40FC Polyurethane PU Sealant that i could use if ok.

I have just covered my flat roof with Ultraflex (Polyurethane). I have now to seal and fix a roof light onto an upstand (that is covered with Ultraflex). When installing the Ultraflex roof they recommended to fill any gaps with Polyurethane sealant as the Ultraflex wont bond to Silicone. With this in mind should I use Polyurethane sealant to stick down the roof light as Silicone wont stick to Polyurethane? Regards, Warren.

So im getting ready to spend cash on the protective layer of my plat roof. So, its about 30mtr2, 150 upstand in the middle for the roof lantern and it will have a build in trough running around two lengths so not completely flat. The roof is south facing. I was looking originally at GRP but there may be issues of cracking with hot cold cycling. EPDM but not sure if it the upstand and inbuild trough would be to fiddly. PU? easy enough to paint on but not sure on toughness or guarantee. Any tips, preferences or pit falls anyone? Regards, Warren.

Currently my VCL is above my OSB. So the vapour will be getting to the bottom side of the OSB and will only get stopped if t gets through the OSB. would have though below the OSB would have been better but may be a struggle stopping the sag. maybe better idea painting something on the underside of the OSB to act as a VCL. that way no screws will ever puncture the VCL unlike what I have now? Warren.

Hello, only gap is between the joist (between top of plasterboard and underside of 1st OSB.

Moving on from my other previous post - I have a warm flat roof made up off - GRP - 18mm OSB3 - 150mm PIR - VCL - 18mm OSB3 - softwood firings - 200x47 C24 joists - Plaster board.. I've a few questions on the VCL bit. Is the VCL just poly sheet? I've no details on the drawing. It is meant to allow vapour to pass through one way as im not sure Polythene will do this? Hunting around ive found that 500 gauge / 125mu 0.125mm thk Polythene sheet is ok but im finding it hard to source? 1000ga and 1200ga is readily available but classed as DPM. Can anyone shed any light on this? Regards, Warren.

Sorry for confusion. not slide, place otherwise I would have to support the top layer of OSB with sky hooks and I've run out. Everything is new. Everything is placed on top of each other, in order, and fixed if required. Big Screws needed to stop it blowing away in wind, earthquake or anything else. Warren

No, this is a new roof, the GRP is on top 🙂

Yes full fixing firings to joists, then temp fixing osb to firings, then slide PIR in, final fix top OSB to Joist, then GRP over the top.

So I have a flat roof. GRP - 18mm OSB3 - 150mm PIR - VCL - 18mm OSB3 - softwood firings - 200x47 C24 joists. worse case bottom of GRP to 40mm inside joist is 290 mm screws at 200mm ctrs which will make the VCL more like a sieve. im also thinking of drilling a pilot hole 5mm down to the joist (make the VCL worse). 3mm gap between each board and 10mm gap around the edges (wall) Questions are. Is hitting 47mm 250mm away achievable? I would think that when board share a joist I would have to double joist? Any thoughts/advise? Warren.

Sheetmaterialswholesale.co.uk - Delivery is £70 and only to local area of which im outside :-(

Mmm, im beginning to think a daft question. Is having formaldehyde in a Warm roof OSB board anything to be concerns with? Normal OSB3 board form China (with formaldehyde) seem to be a third cheaper than Scottish OSB3 (without formaldehyde). I'm presuming that the formaldehyde replacement is very expensive taking delivery from China into account. Regards Warren.

I want to sit my wooden joist (C24) inside a PFC. Or do I need to fix a wooden block and use joist hangers? I have a 150x75 PFC that has an inside ledge of 69mm (although there is a 7.6mm rad). I have 47x150 wooden joist that I intend to sit on this internal face. Data on the NHBC site is a little vague - Solid timber joists - Where connected to steel beams, solid timber joists should: - be deep enough to be notched. Very useful. Does anyone know if 69mm is enough to sit 47x200 on? Regards, Warren.