Ay8452

Hi guys, I am having a single storey extension on my house and trying to find a suitable solution for the following problem. On the side elevation with my adjoining neighbour (semi-d house) their ground level is approx 25cm above my DPM level. I am having beam/block floor in my extension. I have a 70-80mm gap with their ground level. If i out a french drain in here and "tank" the wall with something will that be enough to prevent problems? How deep should the French drain be, 15cm below my DPM level? Drawn a diagram as though I am looking back at the house from the garden, at the rear elevation. Foundations are in and blockwork is about to start. Final spec is cavity wall with render finish. Thanks Ali

Hi Folks, I am doing a single storey extension which was originally specified for a cold flat roof/parapet wall detail. I want to change this to a warm flat roof/parapet wall detail partly because I am going to be adding EWI to the old wall the roof is going to be attached to. Just so I can figure out if I have the correct spec/thickness of everything - is this diagram broadly correct? I am hoping I have enough height to change to a warm flat roof. Will take this to my roofer and designer next week to ask if we make this work over a cold flat roof. (building to current building reg's, foundations in and walls up to DPC currently) - Am I correct in understanding the minimum height f the parapet wall from the external roof deck/GRP is 150mm? - I have going with timber frame for the inner leaf for the parapet wall to eliminate the cold bridge, is this sensible? Thanks Ali

Thank you for your response - why the bitumen paint first?

Hi Folks, I am doing an extension/renovation of my house. I have a few steel beams/columns. I have found a way to bring most/all the steels into the envelope of insulation (warm side) in terms of walls/roof. However I have a few columns that go through the block/beam floor structure and of course the floor insulation (150mm PIR). Steels going through the floors structure - is that as bad as a cold bridge as them going through the walls/roof? Steels are already in so in order to avoid issues I guess the only thing is to wrap the steels in PIR/tape OR aerogyl but it seems overkill/overspend to do that. FYI Steels are in, Beam Block floor is going to be fitted over the coming weeks, there will be a 500mm void below the beam and block. Thanks! Ali

Hi, I could do yes - would the 150mm PIR be a good enough base for the doors?

Hi guys Any glazing fitters who can give me some advice on this? I'm getting conflicting advice at the moment from my fitter/builder. We are fitting Sliding Doors in the kitchen/diner (cortizo cor vision). The horizontal width of the door threshold is approximately 120mm and the doors are fitted flush with outer skin. This means 20mm "overhangs" into the wall cavity (we 100mm inner outer blockwork with 100mm cavity). We have beam and block floor with tiles/screed finish/wet UFH. Can this extra 20mm be fitted to the floor screed? My husband says probably not because the screed won't be strong enough but the glazing fitters say it "should" be fine. We were thinking of just carrying on the concrete mix at the bottom of the cavity up till the door threshold as in the picture below to support the "20mm overhang" of the doors into the cavity to support it. Does this seem sensible? I believe the weight of the door unit is approx 50kg/sqm and door is 4m wide and 2.6m height making the total weight of doors approx 520kg. Thanks Ali

Thanks all for comments. Too late to use two beams unfortunately. If I use aerogel strips and overlap them on the warm side and overlap them either side of the cold bridge area - will that not resolve the cold bridge? I can also apply aerogel externally (cold side) and do the same + plus pack the web with PIR ? Try to make the best of the current situation.

Hi guys, I am doing a renovation and extension of a 1930s house. The extension has a fair amount of steel work and am looking how to sensibly/practically insulate this. What are the recommendations for insulting steel beams and columns? I'll post a couple of scenarios I have below. SCENARIO 1: If the internal web of the steel beam has floor joists etc and the external web is empty/bridging the thermal envelope then pack PIR insulation in the external web/foam and then finish with render board so flush silicone render finish externally. Should I leave a space between the PIR and the renderboard externally to stop moisture ingress? Should I be adding a VCL somewhere internally to this steel? I was considering adding aerogyl strips to the internal aspect of the web (10mm thick) to reduce cold bridging - should this have a VCL added to it? SCENARIO 2: If the internal web of a steel beam is empty and the external web has joists (e.g. flat roof joists for cold flat roof detail) then pack PIR insulation in the internal web and all warm side surfaces of the steel and foil tape it so stop moisture getting to the steelwork. SCENARIO 3: If the internal and external web of a steel beam is empty then pack PIR insulation in the internal web and all warm side surfaces of the steel in the internal web and foil tape it so stop moisture getting to the steelwork. Should I also pack PIR insulation into the external web as well? Have a few other scenarios but will try work those out based on answers for above. Thanks!