deuce22

So, a mineral wool that isn't advertised as acoustic, but is 15kg/m3, should be better than an acoustic insulation that is 10kg/m3? Somebody has contacted me from Knauf and has said that it will have 0 acoustic properties. I'll go with multiple boards then. Thanks.

Hi. Can somebody educate me on soundproofing. I have been told to use 100mm superglass acoustic insulation @ 10kgm3. I have spoke with a soundproofing company about it and they have explained that, it is primarily based on density and it doesn’t matter what the material is. So there were 2 things that I asked. 1. Would 2 standard 12.5mm plasterboards @ 23kg each give better acoustic properties than 1 acoustic board at 31.7 (as I can buy 2 standard boards for a similar price as 1 acoustic board). 2. If an insulation is not marketed as acoustic, but has a heavier weight per m3, than one advertised as acoustic, will this give better performance. He said yes to both. I’d just like to check this because when speaking with Knauf, they didn’t understand what I was asking and couldn’t answer the question. Does anybody know if this is correct? Thanks.

Thanks very much John, for your help. A 25kw boiler will be too much then, the 15kw that a friend suggested looks right. I may find another HE as it looks as if he doesn't know what to do, he hasn't mentioned any of the other things you've suggested.

Sorry, I didn't mean I contacted the plumber, I contacted the company that did the SAP calculations. Is there not a way for me to work out what boiler size I need from these monthly/yearly heat loss figures. I just want to know that the correct boiler is being installed. I know I should trust the HE, but I feel like I need to keep on top of every trade, with the eperience I've had since starting this project.

This is what I've got. I've just contacted them, but they don't know how to calculated the boiler size from the figures shown.

I have had a quick look at my SAP report. Where would I find the info I need? I'll pass some of your advice on to the HE. Thanks.

Thanks for that. I'll input the details and see what it states.

It's a heat only boiler with a 300l cylinder. Underfloor heating on the ground floor, radiators on floor 1 and 2. It's an ICF construction and my friend said straight away that 25kw was overkill. My friend said that oversizing can cause more wear and tear and will waste energy. I don't mind buying the bigger boiler, but will it just cause problems?

Hi. Is there a way I can check what the heating engineer is specifying for my boiler size. He is stating a 25kw heat only boiler, but a friend (who is also a HE, but lives a few hours away, so didn't do the work here), has said it only needs around 15kw. Thanks.

So would a heavier insulation, whether it was marketed for thermal or accoustic, have better sound proofing properties? The plasterer has just told me that he uses standard boards, but doubles them up, rather than using accoustic boards. The double standard board gives better density and is also cheaper. I just want to understand if density is the main requirment for sound proofing. Thanks.

Hi. I am looking for some clarification. Does acoustic insulation have different properties over thermal insulation. I’ve been told, that for soundproofing, it is all about density. If an insulation that is marketed as accoustic, weighs 10kg m3 and an insulation that is marketed as thermal, weighs 15kg m3, will the thermal insulation provide better soundproofing? Thanks.

No, those boards are not there. They've used 200mm+ screws and fixed vertical battens, through the PIR and into the rafter.

No. Im not a roofer, but have an idea of how it all works. I'm now realising that the OSB should have been laid on top of the rafters, with the VCL fitted to this.

roof tile counter batten with breather membrane between 150mm PIR insulation 8x2 rafter with mineral wool between

The ceiling is not up yet. I've spoken with a company that has advised to do the following. Fit a VCL to the underside of the rafters, board and skim, use sealed downlights and seal them to the ceiling with silicone, then use a paint on VCL to the whole ceiling before emulsion. I like the idea of the spotlight shrouds, where do you get these from? Starting to get fed up with tradesmen, just had to go around re-fiting all the door straps into the concrete infill (ICF construction), the fitter used wood screws into the foam only, an almost 1/2 tonned bifold, being held in place by bits of spray foam. Thanks for the help.