vfrdave Posted January 8, 2017 Share Posted January 8, 2017 (edited) We are building a bungalow in the near future and have just had our architect submit to building control. Structural engineer has specified a block on its flat for internal skin of cavity wall. Would anyone be able to provide any insight into the requirement for this. I will attach a drawing for more clarity later. I have queried the requirement but no response as yet. Every builder that has looked at the plans has queried the need. Thanks in advance. Edited January 8, 2017 by vfrdave image added Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 8, 2017 Share Posted January 8, 2017 Replies will likely follow your attachment . Link to comment Share on other sites More sharing options...
Declan52 Posted January 8, 2017 Share Posted January 8, 2017 Normally go that route if you are holding up concrete slabs. If it's only going to be a truss or even a cut roof its a bit overkill. You can use 6*4 blocks if it's holding up slabs. If you go that route it will be twice the amount of blocks plus twice the motar bill plus twice for the bricky to build them walls so think hard as it will definitely add up to the costs. Link to comment Share on other sites More sharing options...
vfrdave Posted January 8, 2017 Author Share Posted January 8, 2017 (edited) Attached drawing 36 minutes ago, Declan52 said: Normally go that route if you are holding up concrete slabs. If it's only going to be a truss or even a cut roof its a bit overkill. You can use 6*4 blocks if it's holding up slabs. If you go that route it will be twice the amount of blocks plus twice the motar bill plus twice for the bricky to build them walls so think hard as it will definitely add up to the costs. No slabs in this case cut roof as per drawing. I am well aware that block, mortar and labour will essentially double never mind twice the mortar to fall in cavity. I think it is overkill and can't understand what it is for, architect just said SE specified, but I'm no expert. It also creates quite a deep window reveal which isn't ideal. Edited January 8, 2017 by vfrdave roof not riff Link to comment Share on other sites More sharing options...
Mr Punter Posted January 8, 2017 Share Posted January 8, 2017 Ask the engineer to look at it again. Maybe some of the walls can be 100mm. Link to comment Share on other sites More sharing options...
Declan52 Posted January 8, 2017 Share Posted January 8, 2017 (edited) Are the steel beams going from gable to gable resting on a few internal walls along the way. Hard to make out on my phone as I dropped it yesterday and it's screen is a shattered mess!!! If so could you get away with 150mm on the gables and 215mm on the internal walls where two beams meet. Edited January 8, 2017 by Declan52 Link to comment Share on other sites More sharing options...
ProDave Posted January 8, 2017 Share Posted January 8, 2017 That looks a very heavily over engineered structure for a bungalow. Is it in a particularly exposed location? I would be talking to the SE to ask why all those heavy engineering details. There is a lot there that looks very expensive to build. When my house was first designed, the SE specified a very complicated looking racking panel in each corner that would have been a difficult thing to build and looked like it would be a massive cold bridge. I queried it and he came up with something else a lot easier to build. Link to comment Share on other sites More sharing options...
vfrdave Posted January 9, 2017 Author Share Posted January 9, 2017 9 hours ago, Declan52 said: Are the steel beams going from gable to gable resting on a few internal walls along the way. Hard to make out on my phone as I dropped it yesterday and it's screen is a shattered mess!!! If so could you get away with 150mm on the gables and 215mm on the internal walls where two beams meet. Yes beams are running gable to gable and resting on a few internal walls, it should be noted though that the internal walls have only been specified as 100mm as you would expect. Link to comment Share on other sites More sharing options...
ProDave Posted January 9, 2017 Share Posted January 9, 2017 But it's a trussed roof. Why can't that just support on the outside walls? what's the span front to back? He seems to be specifying a ridge beam and 2 purlins which you would expect for a cut roof, then specifying trusses? Link to comment Share on other sites More sharing options...
Declan52 Posted January 9, 2017 Share Posted January 9, 2017 Could you not just use attic truss on the whole roof and just a small bit of a cut roof over the reception area. Link to comment Share on other sites More sharing options...
ProDave Posted January 9, 2017 Share Posted January 9, 2017 2 minutes ago, Declan52 said: Could you not just use attic truss on the whole roof and just a small bit of a cut roof over the reception area. That is what I would do and it leaves the possibility of a cheap and easy loft conversion later. Link to comment Share on other sites More sharing options...
Daedalus Posted January 9, 2017 Share Posted January 9, 2017 You seem to have a lot of openings in some sections of the wall, are these full height? If so its probably so the walls can take a wind load along that face? Just a guess mind. +1 to attic trusses being cheaper and easier, although you would lose that nice vaulted roof look at the end. Link to comment Share on other sites More sharing options...
vfrdave Posted January 9, 2017 Author Share Posted January 9, 2017 47 minutes ago, ProDave said: But it's a trussed roof. Why can't that just support on the outside walls? what's the span front to back? He seems to be specifying a ridge beam and 2 purlins which you would expect for a cut roof, then specifying trusses? The span external - external 6.38, it should be noted no facia and soffit and therefore no overhang. It is a cut roof, feature trusses specified above kitchen/dining where we have a vaulted ceiling. 7 minutes ago, Daedalus said: You seem to have a lot of openings in some sections of the wall, are these full height? If so its probably so the walls can take a wind load along that face? Just a guess mind. +1 to attic trusses being cheaper and easier, although you would lose that nice vaulted roof look at the end. Openings aren't full height they will run approx level with internal doors. Some areas may change to standard truss as we will not have access to those roof spaces, bedrooms will remain either cut or attic trusses. Some of the builders I have spoken with are going to price both however claim that other than the difference in labour required there wont be much of a difference in price. Link to comment Share on other sites More sharing options...
Declan52 Posted January 9, 2017 Share Posted January 9, 2017 When I priced mine up the price of steel made a cut roof over £3k more expensive. Send your plans of too a few truss companies and see what they price it at. I got five quotes for my roof before I bit the bullet. Link to comment Share on other sites More sharing options...
vfrdave Posted January 9, 2017 Author Share Posted January 9, 2017 1 hour ago, Declan52 said: When I priced mine up the price of steel made a cut roof over £3k more expensive. Send your plans of too a few truss companies and see what they price it at. I got five quotes for my roof before I bit the bullet. Any recommendations on the supplier front? Link to comment Share on other sites More sharing options...
ProDave Posted January 9, 2017 Share Posted January 9, 2017 What's the size of the bit with a vaulted roof? It might make more sense to have most of the roof with attic trusses, and the vaulted bit as a cut roof supported on Glue Laminated timber beams which can be sanded and made into an exposed feature. Link to comment Share on other sites More sharing options...
vfrdave Posted January 9, 2017 Author Share Posted January 9, 2017 38 minutes ago, ProDave said: What's the size of the bit with a vaulted roof? It might make more sense to have most of the roof with attic trusses, and the vaulted bit as a cut roof supported on Glue Laminated timber beams which can be sanded and made into an exposed feature. 6.38 x 8m Link to comment Share on other sites More sharing options...
Declan52 Posted January 9, 2017 Share Posted January 9, 2017 I went with ATS truss in Portadown but I had prices from Murdock's, Quinn's in coalisland, Haldane fisher, Hawthorne in south Armagh and a few others. I also have a vaulted section over the stairs which was a cut roof. It is only 2.5m wide and took the joiners as long to do it as spread and brace the rest of the truss roof. Link to comment Share on other sites More sharing options...
vfrdave Posted January 10, 2017 Author Share Posted January 10, 2017 Just to keep this updated I have now had a response from the SE stating that the reason for the 215mm inner leaf is required to make the perimeter walls comply with wind loading design regulations for a combination of reasons namely; · Large open plan internal spaces · Higher than normal ceiling heights (2.8m compared to 2.4m normal) · Large window openings and corner windows @Daedalus you were correct. Link to comment Share on other sites More sharing options...
Daedalus Posted January 10, 2017 Share Posted January 10, 2017 Always am ... ... Link to comment Share on other sites More sharing options...
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