MasonC

Makes sense going 2x7 to avoid the internal battens, did you do anything in regard to cold bridging with the timbers. Also how did you allow for continuity of the VCL?

I have 150mm between the timbers and was going to have a battened service void internally and battened externally for the render board and cladding.

I was wondering if anyone could help with choosing the insulation for our front extension build. My friend who is an experienced carpenter and is going to be building the front porch with me alongside suggested using Actis insulation. However being technically minded I thought I'd dig into Actis before hand as I had presumed I would go for PIR. However my understanding from this forum is Actis relies pretty much only on the air gaps required in the full system and in itself provides very little insulation qualities. PIR wise my current understanding is that it may not be great from a decrement delay standpoint. Therefore I'm thinking of using a mineral/glasswool product. The extension is currently on the old building regs value requirement but I'm thinking if I can get more in for a similar cost then great but its not a long term home for us so cost is something I care about most. The Actis buildup we were looking at: BOOST'R HYBRID 35mm HYBRIS 155mm HCONTROL HYBRID 45mm According to their simulator that would achieve 0.12m2k. So if I could hit that U value or better for a similar or less cost then that would be great. The current finish would be ground floor render board and First floor cladding. Any ideas or help would be greatly appreciated.

If you're going to cover the roof in a ballast or sedum trays I would consider a single ply or felt system. While both single ply and EPDM both have the con of being prone to puncture Single ply at thicker gauges i.e. 1.8 is extremely resistant and if your covering in ballast you will be required to have a protection layer over the single ply which coupled with your ballast or green roof would make it bomb proof to punctures. Alternatively just use a felt system which would give e you the robustness you want a high longevity and it would eliminate the 18mm ply. Felt systems like Bauder and Icopal are tired and tested but everyone is doing them now Sika has a system and so do Iko it depends on your budgetary requirements. Bauder also do their own green roof systems which then fall under their guarantee as well though.

Rockwool is the architects specification of choice it seems. its perfectly fine to walk on to start with very similar to PIR but I become spongy quickly, we found every normally by the end of the build. Iko all do their own brand of mineral wool though. Liquids not too bad if installed correctly and the application is suitable. it was our preference for all hight traffic areas (balconies etc.) to be done in liquid but the m2 cost is just stupid compared to felt which is perfectly fine for high traffic areas. Some people preferred Hot melt but there is the big H&S push towards flame free so liquid wins out there, however felt manufactures have create flame free systems, basically self adhesive felt.

Is there any reason you have chosen to go with a liquid system? I would eliminate the ply above the insulation an go for a single ply membrane bonded straight to foil face(better U value) PIR insulation(you may be forced to use tissue faced board if the brand doesn't use a contact adhesive compatible). PIR insulation will be good if subjected to light traffic and would only become spongy after quite a few years. Mineral wool insulation however goes very spongey very fast if walked on. When we used mineral wool on high traffic areas like maintenance walkways on hospitals we put a galvanised metal sheet(wrapped in fleece) on top of the membrane and attached membrane over the top to spread the load.

Hi all, My wife and I bought and Ex-Council house to refurb and extend both for practicality and for a bit more space. The plans have been in for a while and look to go through in January now after being postponed due to the volume in our parish council. We are doing most of the work ourselves but subbing out to the skilled trades. We are fairly competent and push our limits as much as possible. I’ve got a background in Estimating Commissioning of Commercial water and air systems and then Estimating Commercial Roofing & Cladding but have jumped over to become a Trading Standards Officer… a fun conversation with trades people! (Shortly followed by a “don’t worry”!) Joining the forum for help with any areas we may get stuck on. There are plenty being thrown up as we start to scratch the surface! In fact I’ve just posted our first problem here:

Hi, don’t know if anyone can help me unpick this. We pulled out the gas fireplace that was previously installed and removed everything back to the original chimney breast brickwork. As we did that it became apparent that the person who installed it hacked the right angles off the fireplace brickwork. We are planning on lining the recess with Hardie board, but I am worried that where the board meets at a right angle the void behind it will render the board unstable or prone to break. I think the best option is to pack it out, but I have no idea what to pack it put with… (apart from mortar but I am concerned it won’t key in enough and wouldn’t know the correct mix for what I want, and would I have to shutter it etc…) Any help or suggestions would be great. Lots of pictures attached. The Ply is just for demo purposes