Pocster Posted March 31, 2017 Author Share Posted March 31, 2017 Actually I presume which ever firm supplies the trusses etc could also do the timber frame and their own SE could sign it off ? Link to comment Share on other sites More sharing options...
PeterW Posted March 31, 2017 Share Posted March 31, 2017 You would need to ask them. The better way is to get the structural timber frame up first as you need to tie the two together and you can't do that from the inside. Link to comment Share on other sites More sharing options...
Pocster Posted March 31, 2017 Author Share Posted March 31, 2017 15 minutes ago, PeterW said: You would need to ask them. The better way is to get the structural timber frame up first as you need to tie the two together and you can't do that from the inside. Ok I could put ties on my external block work - ready for tieing to timber frame work cheers Link to comment Share on other sites More sharing options...
Triassic Posted March 31, 2017 Share Posted March 31, 2017 (edited) You should be erecting the timber frame first, as it needs to be covered in vapour membrane and the joints taped to meet air tightness Regs. You can't do the external block work first, it's the wrong way to go about things! edit . Just a thought, my SE required the outside face of the timber frame to be covered in 11mm OSB to provide strength, this would make it impossible to tie the timber frame to the blockwork. Edited March 31, 2017 by Triassic Link to comment Share on other sites More sharing options...
Pocster Posted March 31, 2017 Author Share Posted March 31, 2017 Ok as far as I understand it the timber frame is self supporting so wouldn't need ties . why not build external block work then timber frame with membrane then roof structure ? Link to comment Share on other sites More sharing options...
Construction Channel Posted March 31, 2017 Share Posted March 31, 2017 You really do want to do the frame first. I had to put my back wall ( timber frame) against an existing wall and it was nothing but a PITA. Link to comment Share on other sites More sharing options...
Pocster Posted March 31, 2017 Author Share Posted March 31, 2017 Ok there seem to be some mutually exclusive things here ! ties to bind the 2 leafs - but can't break vapour membrane ? timber frame is self supporting so no need to fix to outer leaf - I can't anyway insulation in the way . Link to comment Share on other sites More sharing options...
PeterW Posted March 31, 2017 Share Posted March 31, 2017 Ties for timber frame are screwed to the outer surface of either the timbers or the OSB if present. The screw and tie will cover any hole in the membrane. An external single skin of blockwork is not self supporting at 3m tall and is dangerous - it has to be tied back to the frame as even wind suction could pull it over. Do you have the full set of plans for the design ..?? 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 31, 2017 Share Posted March 31, 2017 As above, the structural timber frame MUST be erected first, and almost certainly signed off as being in accordance with the SE's design by BC. Then you can start building the outer leaf, which is non-structural and only there to keep the rain off. The outer masonry leaf MUST be tied to the inner structural frame, at the approved tie spacing. Failure to do this will result in a failure similar to that which closed schools built in Scotland under a PFI, where the ties weren't adequate and the walls fell down in a wind. What's building control got to say? They presumably have the SE's design calcs and drawings, in order to have signed it off against Part A, so all you need to do is follow the SE's instructions and you should be fine. Link to comment Share on other sites More sharing options...
Brickie Posted March 31, 2017 Share Posted March 31, 2017 (edited) Whoaaaaa there!! your timber frame needs to go up first,roof on,windows & doors fitted,then your outer skin is built with ties fixed to the studs & lintols over openings also restrained back against the frame. It's about 10 years since I worked on a timber frame,but at that time we were leaving compression gaps above & below all openings in the masonry. Think all the ones built in the 70's have issues with door frames squashing up as the building settles over the years. Edited March 31, 2017 by Brickie Not enough whoa 1 Link to comment Share on other sites More sharing options...
Pocster Posted March 31, 2017 Author Share Posted March 31, 2017 Ok I get the point :-) but what's wrong with external wall with ties then internal timber frame being assembled in that order ? what problem does this present ?? my SE has disappeared ! Hence on my own a bit ...... Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 31, 2017 Share Posted March 31, 2017 (edited) Firstly, building it ass about face will mean you won't be able to fix the ties to the frame, as they are fixed from the outside. Secondly, an unsupported single leaf will be more liable to fall over under wind loading, when it gets above about a metre and a half high, unless it's propped. Finally, how are you going to fit the cavity insulation if you build it backwards? Edited March 31, 2017 by JSHarris Link to comment Share on other sites More sharing options...
Roundtuit Posted March 31, 2017 Share Posted March 31, 2017 The ties are generally nailed to the osb that clads the frame, and bedded into the mortar joints of the outer masonry skin. Not sure how how effectively you could do it differently. Link to comment Share on other sites More sharing options...
Triassic Posted March 31, 2017 Share Posted March 31, 2017 The timber frame is the structural element that supports everything, including providing ties to support the block work. Link to comment Share on other sites More sharing options...
Pocster Posted March 31, 2017 Author Share Posted March 31, 2017 1 minute ago, JSHarris said: Firstly, building it ass about face will mean you won't be able to fix the ties to the frame, as they are fixed from the outside. Secondly, an unsupported single leaf won't stay plumb, and will be liable to fall over under wind loading, when it gets about about a metre and a half high. Finally, how are you going to fit the cavity insulation if you build it backwards? Hmmmm ive been told that if I bed my ties in the external block work they can tie to the timber frame internally - though I must admit I don't know how . re insulation . External wall with ties . Then insulation . Then protruding ties onto timber frame work . Told this by a builder ..... Link to comment Share on other sites More sharing options...
Steptoe Posted March 31, 2017 Share Posted March 31, 2017 you have to build the structural element first, in your case, the timber frame, then build the covering, in your case the outer blockwork, what you are doing is like trying to build a metal clad shed by screwing all the cladding together first and then trying to build the metal framework afterwards there is nothing there to hold the cladding together. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 31, 2017 Share Posted March 31, 2017 Sounds like making a rod for your own back to me. It's dead easy to fix ties to the outside of the structural frame, as you build up the outer skin, so you get them in the right place. It's also dead easy to fit the cavity insulation as you build up the outer skin. I can't see any reason at all why you should try and do things the wrong way around. Link to comment Share on other sites More sharing options...
Construction Channel Posted March 31, 2017 Share Posted March 31, 2017 8 minutes ago, pocster said: Hmmmm ive been told that if I bed my ties in the external block work they can tie to the timber frame internally - though I must admit I don't know how . re insulation . External wall with ties . Then insulation . Then protruding ties onto timber frame work . Told this by a builder ..... Just don't do it, you want to be putting OSB on the outside of your timber frame even if you haven't been told to as it helps stiffen everything up (raking strength i think its called) the way your "builder" friend is suggesting has nothing stopping any moisture in the cavity getting at your structural timbers which to me sounds like a bad idea. Timber studs - Osb- breather membrane- ties bricks/blocks (rain shield) `edit: plasterboard - vapour barrier - timber studs ....ect Link to comment Share on other sites More sharing options...
Pocster Posted March 31, 2017 Author Share Posted March 31, 2017 Guess I need a new SE !!!!! Link to comment Share on other sites More sharing options...
Construction Channel Posted March 31, 2017 Share Posted March 31, 2017 1 minute ago, pocster said: Guess I need a new SE !!!!! Not really just talk to your local BCO. Im fairly sure they will say the same 1 Link to comment Share on other sites More sharing options...
RichS Posted March 31, 2017 Share Posted March 31, 2017 The drawing states breather membrane on ply sheathing etc etc etc. You can't possibly build that arse about face. Link to comment Share on other sites More sharing options...
Construction Channel Posted March 31, 2017 Share Posted March 31, 2017 3 minutes ago, RichS said: The drawing states breather membrane on ply sheathing etc etc etc. You can't possibly build that arse about face. technically he could build it in panels and put the membrane on while they are still on the ground, (I had to on my back wall) But its a stupid idea and you couldn't tie the two skins together afterwards anyway so as advised above, just don't do it.... 1 Link to comment Share on other sites More sharing options...
Ian Posted March 31, 2017 Share Posted March 31, 2017 (edited) 31 minutes ago, pocster said: Ok I get the point :-) but what's wrong with external wall with ties then internal timber frame being assembled in that order ? what problem does this present ?? my SE has disappeared ! Hence on my own a bit ...... Sorry to be blunt but there's no real way of sugar coating this - you urgently need to get some professional help with this build. Your questions demonstrate a basic lack of understanding of simple construction issues and it's some of the scariest stuff I've ever read on a self-build forum. What involvement have you had so far with your Building Inspector? Have they approved your foundations? Edited March 31, 2017 by Ian 1 Link to comment Share on other sites More sharing options...
Brickie Posted March 31, 2017 Share Posted March 31, 2017 You will also need the frame up first in order to install a cavity tray at g/f level. There are lots of people on here to help (& that's what we're here to do,not to patronise) so please take the advice given to get some professional help in. At the very least,write off the next week as far as progress goes & post as many pictures,architects drawings etc as you can. I can't imagine the stress of a self build-tackling diy outside my own sphere of knowledge is bad enough so I'd hate to see things south for you. 3 Link to comment Share on other sites More sharing options...
Triassic Posted March 31, 2017 Share Posted March 31, 2017 The bottom line is that we are here to help, you do really need to get the timber frame up first, once you have the roof on, the vapour membrane on the outside and windows in, you will be water tight. Then you can concentrate on the outside rain screen block work . Link to comment Share on other sites More sharing options...
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