bmj1

As per the topic, is there any feasible way at all to add an extra row of tiles ?

That's totally fine. 10% + a fitting charge is totally reasonable. And I'll handle the cashflow. I'm just wondering if this is crazy talk in principle?

Understood. But paying tens of thousands feels ludicrous to me for pvc sash windows..

OK, so: I've sourced the windows we like, and negotiated trade pricing with the window manufacturer (which I've had confirmed is the same as any fitter will get). ~35 PVC sash windows in total. We're in North London Am I crazy to think we can organise measure & fitting of these, and ask our main contractor to order the windows for us supply-only (to save us fronting the VAT) ? When I've tried to source these supply+fit the mark-ups have been really crazy...

Hi all, When is the earliest I can use a thermal camera on our project to check for issues with gaps in insulation, etc ? E.g. once all windows are in ? Many thanks in advance

I've got space for insulated plasterboard internally, just wondering if a risk of condensation?

This is a very clever idea. Would need the planning conditions worded right. The only thing I don't like is it might complicate the demolition (do you really want a 23 tonne digger anywhere near your brand new foundations?)

Hi all, We've got some rooflights built like this: I'm not entirely sure on the insulation in the upstand (if any). Is there any reason not to use a insulated plasterboard here (17mm PIR + 9.5mm plasterboard), in order to reduce the thermal bridging ? (My concern is of creating interstitial condensation)

Awesome, thank you !

A constraint. But I'm ok with it. I'm planning to have each room zoned with heatmiser. Tbh - instant response sounds good to me. I'm not sure I understand why we would want to wait an hour to feel the benefit of the heating ?

Very tight. ~120mm total for insulation + screed (to include underfloor heating)... I managed to pick up 75mm phenolic for £20/sheet from Secondsandco (link), so I think that's the best result I can hope for given the situation.

What screed did you use? I'm planning 40mm liquid screed to maximise heat transfer

Insufficient in terms of sap calcs? Or the house feels cold/is costly to heat? Are you using a heat pump ?

Ok fab. Out of curiosity, how thick did you go ?

Sure. Only thing is it isn't PIR, it's the phenolic product. K103 So not quite sure how it behaves !

Hi wise people, Was planning to do underfloor heating with liquid screed over kooltherm phenolic insulation. Kingspan advise that this insulation should not get wet, so plastic sheet above. So how do we do the clips for underfloor heating without piercing the insulation ?

Thanks, makes sense. DPM below and above then. I've grabbed some 75mm Kooltherm from Seconds and Co.. (£400 / pallet of 20 sheets). Can't go wrong at that price. My max was 90mm, but that was pushing it on tolerance. This is much more comfortable. Gets us a floor u-value of 0.157, which we'll compensate for with solar PV. I'd rather have the extra ceiling height than a slightly more energy efficient house.

Yes, London Clay

I'm a bit confused by the K103 product: K103 insulation is designed for floor insulation in floor buildups. You can install K103 phenolic foam boards in block and beam, solid concrete, suspended ground floors and timber floors. The insulating core is surrounded by glass tissue facings. Why do they surround it by glass tissue facings ?

Our GF build up is: Beam & block DPM PIR insulation Liquid screed Floor finish Should the PIR insulation layer be foil or tissued faced? One-side or both sides ? Or should we be putting a plastic membrane between the PIR and liquid screed, in which case tissue facing is fine ? Thank you in advance.

I think you need to remove the foundations to save the vat with a new build

Thank you all for the advice ! Does having MVHR help at all with the condensation risk flagged ?

Hi all, I've got a flat roof problem to solve. Roof is already built and sealed watertight. Was spec'd as 125mm above / warm roof. Built as 100mm above / 25mm between rafters. Architect wants us to rip out and add above. Building control says it's fine if the insulation between is pressed up against the bottom of the plywood, to form 1 layer. All insulation is as 0.022. Options 1) Rip off roof and rebuild 2) Remove the insulation between the rafters 3) Something else ? Advice gratefully received ! Many thanks in advance.

Are you saying that as a good thing that it sucked up the moisture ?

How about this ? https://www.ready2pour.co.uk/liquid-floor-screed/gypsol-ts-15/