bmj1

Just to add, here is my floor layout (this photo taken 9 months ago when we were at this stage)

Honestly, that's a relief to hear ! We're planning underfloor heating, and my preference was liquid screed (I think we can get this down to ~50mm ?). I've got 120mm total to play with above the beam/block floor, minus say 20mm for the floor finish and 50mm for liquid screed.. So room for PIR or some kind of board or potentially both..

Sounds good to me. Can anyone recommend alternatives to Beamshield ? Planning to hit the phones hard on Monday AM and would be good to have 2 or 3 companies in mind to tap up for this. I did look at Milbank Warmfloor Pro, but they appear to require 75mm of concrete on top, which is self-defeating in terms of minimising floor build-up... Thanks in advance

Wow - thank you all so much. I really like the sound of this solution vs VIPs, both for ease of installation and also durability over lifetime of the house. Yes, I can confirm the walls and upper floor are built. Is removing the concrete blocks from the beam+block floor still doable at this stage ? It looks to me like it is sealed in somehow ? Here is how the floor looks right now...

That's an interesting idea. It actually was designed right, but the implementation was botched... So you are suggesting that we remove the blocks between the beams, and replace with insulated ones. Neat. Any blocks you have in mind ?

Hi All, I've found myself with just 120mm of floor build up above Ground Floor block and beam solid concrete floor. I'm trying to figure out what our floor build up can look like to enable us to have underfloor heating, here is where I've got to: 50mm - VIPs 50mm - liquid screed / underfloor heating 20mm - floor A) Can this work ? B) Any recommendations in terms of VIP flooring providers ? Thank you in advance !

I'll call them in the morning and ask how we skim it. I guess my alternative question is if anyone is aware of a very strong, thin plasterboard / plasterboard alternative ? (that could be bonded to the PIR instead of PB)

Concrete blocks. So the third party company will bond the PIR onto the Magply for us, and then we do the dot/dab of the combined product and skim. Does that make sense?

I.e. that's a build up of: 10mm dot+dab + 15mm PIR + 6mm Magply + 3mm skim = 34mm Plasterboard is of course thicker than the Magply

Hi Conor - my thinking was the Magply is instead of PB. Does that make sense ?

Hi all, We need to dryline our walls (cavity construction, concrete inner skin, brick outer) to bring up our u-values. I'm trying to keep the wall build-up minimal. I've found a company who can bond 15mm of PIR to 6mm Magply, which we can then dot + dab on. I'm not familiar with plasterboarding / MGO alternatives, has anybody here used Magply? Will I be okay with a 6mm thick magply for my walls ? Any other issues/concerns to flag up ? I guess hanging joinery (e.g. in kitchen) might need to be fixed all the way through to the concrete substrate ? Thank you so much in advance.

wow, awesome, thank you. This should be easy enough to specify and explain with your picture and comments

Hi all, We've got our shell erected, brick and block cavity wall construction. I'm looking to retroactively bring our wall u values up, and it looks like drylining with insulated plasterboard is the only realistic option. I was previously hoping to use wet plaster for the "easy" air tightness, but this doesn't appear to be feasible... Any recommendations for how we can best ensure we get decent air tightness with insulated plasterboard dot and dabbed onto concrete blocks? Parge coat? Tape applied where? If anyone can give me a bullet proof spec, that would be awesome. Thank you in advance

I believe we've got Rockwool 032 in there. I've come across this product, as an option for dry lining. What would be even more ideal would be 15mm of this PIR product, bonded onto 3mm of MGO board. Any thoughts on how I might procure such a thing ? Or ideas for alternatives ?

Hi all, When hiring a main contractor for a large project, would you advocate liquidated damages clauses, or is it felt these are a bad idea as would be expected to be mutual, or might create a pressure to rush things? Thoughts gratefully received!

I'll get it tomorrow. Which spec details would be helpful ? R value ? U value ?

Why do you rule out blowing additional insulation into the cavity ?

Ok. But does it add to the wall build up in terms of thickness ?

Yes. FYI we're under previous version of building regs as planning granted in first 2021 so not quite as tight. However, 150mm of rockwool would obviously work much better. We had a SAP consultant do the design, was originally spec'd as 100mm K108, but taking out the existing rockwool would be a mammoth task, so that's why I'm trying to think creatively here... We're in London, so price per square foot means we'd be much better filling the cavity if at all possible. I'm not ruling out some kind of thermal lining, but this is last resort. I'll be grateful for any further thoughts.

Our structure is fully erected. We've got 150mm deep cavities (for deeper reveals), and they are currently filled with 100mm of Rock wool 032 cavity wall insulation, and 50mm void. I'd like to increase our u value of our cavity walls... Lining on the inside would be gutting as we would lose space. Can I blow in more rockwool insulation to fill the 50mm void ? Any reasons not to do this ? Thank you in advance

Lintels are the design of the attached (not this brand), i.e. the steel slopes towards the outer leaf.

Thanks all. To be clear it is a single galvanised steel cavity lintel, so there is bridging straight across the cavity. Psi value is ~0.55, so it's material on the SAP. It's deep reveals. 150mm cavity. Plan is for whole house mvhr. Keen for your follow up comments. Thank you! @Mr Punter @nod @Miek @Brickie @PeterW@Iceverge @Temp

Hi all, We're at ridge level now, which is super exciting... however, I've hit a bit of a snag when reviewing progress to date.. we've had some material substituted by the main contractor to use regular cavity wall galvanised steel lintels, instead of the hi-therm/insulated. We've now paused all progress on site while we review state of play. My question is as follows: - Putting aside all the impact on thermal performance, and SAP, etc, which we can compensate for (and live with), in practice, how much of an issue is this likely to be in terms of causing mould ? If this is a problem, is there a solution that doesn't involve replacing all the lintels ? Many thanks in advance.

Very exciting! I'm afraid it takes a little longer to go up... Hope all continues to go smoothly for you

"The contractor who build the house (brick work) charged us vat 20%" All supply and fit work should be zero rated for VAT. You won't be able to reclaim this VAT from HMRC. You need them to void the original invoice and issue you a correct one, and refund you the overpayment. You might need to pay them an admin fee for the trouble. Going forwards, any supply+fit works needs to be zero rated at invoice stage. Providing them a copy of your new build planning permission is usually sufficient for this.