Broughs8286 Posted May 6 Share Posted May 6 Hi! The rafters in our loft have been sistered on one side before us and the previous owners. Much to many a dismay we didn’t have a structural survey when we bought the house, just the valuation survey required by the mortgage company. We bought this house very quickly. We’ve not got any or had an issues - our loft is dry, no evidence of dry rot, no signs of warping, no signs of sagging both in the loft and also on the roof so we’re reasonably confident our roof and loft are fine. We’re just unsure why one of the side roof would’ve been sistered? Is it a sign something is wrong? Or was wrong? Would sistering have made this strong enough to do its job? Has the sistering been done properly? We note the sisters don’t extend all the way to the apex - is this correct? Anything we can add to support it? We’re just planning to board out, as we’ve already started to do, for general storage purposes (nothing particularly heavy). We’ve got a chartered surveyor lined up ready to survey the roof and loft should we think it’s a good idea. We just don’t know if we’re worrying over nothing and if you regularly inspect your loft and roof that you’ll notice if and when something is wrong? We have recently had a new water cylinder installed in the loft (associated with our heat pump) but the installers built a wooden platform spanning several joists to spread the weight. What does everyone think? Link to comment Share on other sites More sharing options...
joe90 Posted May 6 Share Posted May 6 Does the roof sag at all that side ? If not I can see no reason for it. Also additional timbers added to other bits don’t IMO serve any purpose. Have they added solar panels above the sistering, which might be why additional strength was added. 1 Link to comment Share on other sites More sharing options...
ProDave Posted May 6 Share Posted May 6 Has a rear extension been built and the end of the extension roof is now sitting on the reiforced bit? 1 Link to comment Share on other sites More sharing options...
Broughs8286 Posted May 6 Author Share Posted May 6 Thanks for your replies so fast! No the roof doesn’t sag on the side with the reinforcements. And no solar panels either. Perhaps someone previously was preparing to have panels then didn’t? no rear extension built either. The little horizontal sections of wood on the other side have been added because we plan to run some mesh down to allow birds to use that dead space but so they don’t run about our loft space. Link to comment Share on other sites More sharing options...
joe90 Posted May 6 Share Posted May 6 3 minutes ago, Broughs8286 said: The little horizontal sections of wood on the other side have been added because we plan to run some mesh down to allow birds to use that dead space but so they don’t run about our loft space. Ooh I would not do that, it will stink in a short period of time, much better to build bird boxes outside in their natural environment. 1 1 Link to comment Share on other sites More sharing options...
Broughs8286 Posted May 6 Author Share Posted May 6 Oh sure - the birds are already nesting there, accessing the roof through the underneath by the guttering/roof tiles. But you’re right, perhaps bird boxes would be better. How would you go about sealing off all access from outside? Might sound like a daft question Link to comment Share on other sites More sharing options...
jayc89 Posted May 6 Share Posted May 6 8 minutes ago, Broughs8286 said: Oh sure - the birds are already nesting there, accessing the roof through the underneath by the guttering/roof tiles. But you’re right, perhaps bird boxes would be better. How would you go about sealing off all access from outside? Might sound like a daft question Eaves combs are your best bet, but you need to remove the first row of tiles/slates to fit them. 1 1 Link to comment Share on other sites More sharing options...
joe90 Posted May 6 Share Posted May 6 +1 also you could fir eaves trays if the felt is a bit old. https://www.trulypvc.com/roofing/fascia-soffit/eaves-protection/1.5m-eaves-protector-felt-support-tray-5-pack 1 Link to comment Share on other sites More sharing options...
Iceverge Posted May 6 Share Posted May 6 I would bet they fell off the truck and fractured or someone accidentally ran a circular saw across the top chord or some other damage. They were then reinforced as shown. Perfectly sound I would say. 1 Link to comment Share on other sites More sharing options...
joe90 Posted May 6 Share Posted May 6 2 hours ago, Broughs8286 said: Might sound like a daft question Remember there is no such thing as a daft question, daft is not asking, we all had to start somewhere 👍 yes Coombs and eaves trays best way to stop birds getting in but still allow ventilation, eaves trays support roofing felt that often fails near the gutter so will extend the like of you roof. 1 1 Link to comment Share on other sites More sharing options...
Broughs8286 Posted May 7 Author Share Posted May 7 Thanks Joe! Yes you’re right, better to ask when you don’t know! Do you think we should sister the rafters on the other side so the weight is uniform? I wouldn’t want one side to be reinforced and then the other side to flex more? Link to comment Share on other sites More sharing options...
Broughs8286 Posted May 7 Author Share Posted May 7 And can we take out the first road of tiles ourselves? Or do we need a roofer to do that for us? Link to comment Share on other sites More sharing options...
joe90 Posted May 7 Share Posted May 7 13 minutes ago, Broughs8286 said: Do you think we should sister the rafters on the other side so the weight is uniform? I wouldn’t want one side to be reinforced and then the other side to flex more? Personally I don’t think those sister pieces of wood weight very much compared to the whole weight of the roof it’s more about sagging which you can measure with a piece of string tied to a nail at one end of the roof (half way down the slope, )pull it tight and go to the other end of the roof, when the string touches the middle joist how far from the joist at the end you are holding! (I hope I described that ok?) some sagging is inevitable but will give you an idea. 18 minutes ago, Broughs8286 said: And can we take out the first road of tiles ourselves? Or do we need a roofer to do that for us? Very DIYable, biggest problem is access, a scaffold tower or scaffold, don’t try this from a ladder. 1 Link to comment Share on other sites More sharing options...
George Posted May 7 Share Posted May 7 I can't see any diagonal bracing or binders. I suspect the roof warped a bit and was straightened/strengthened with the extra timber. The 'noggins' are especially suggestive of that. The survey will probably advise bracing is added. 1 Link to comment Share on other sites More sharing options...
Broughs8286 Posted May 7 Author Share Posted May 7 (edited) Hi George! Thankyou for your reply! Which bits are the noggins? If you’re referring to the little horizontal bits between the rafters, we’ve added those as we were going to box in some of the wasted loft space for birds but have decided against that. If we were to brace, where would we brace? What type of braces would we need? Edited May 7 by Broughs8286 Typo Link to comment Share on other sites More sharing options...
Broughs8286 Posted May 7 Author Share Posted May 7 2 hours ago, joe90 said: Personally I don’t think those sister pieces of wood weight very much compared to the whole weight of the roof it’s more about sagging which you can measure with a piece of string tied to a nail at one end of the roof (half way down the slope, )pull it tight and go to the other end of the roof, when the string touches the middle joist how far from the joist at the end you are holding! (I hope I described that ok?) some sagging is inevitable but will give you an idea. Very DIYable, biggest problem is access, a scaffold tower or scaffold, don’t try this from a ladder. good point about needing a scaffold tower. We might do everything in one go - clean the roof of moss, add eave Coombes and trays, clean the gutters etc. just a roof once over! Link to comment Share on other sites More sharing options...
George Posted May 7 Share Posted May 7 9 minutes ago, Broughs8286 said: Hi George! Thankyou for your reply! Which bits are the noggins? If you’re referring to the little horizontal bits between the rafters, we’ve added those as we were going to box in some of the wasted loft space for birds but have decided against that. If we were to brace, where would we brace? What type of braces would we need? It's usually just 4x1" planks, double nailed and lapped to the underside of the trusses. https://nhbc-standards.co.uk/7-roofs/7-2-pitched-roofs/7-2-9-bracing-for-trussed-rafter-roofs/ https://www.tra.org.uk/download/2572/ 1 Link to comment Share on other sites More sharing options...
Broughs8286 Posted May 7 Author Share Posted May 7 9 minutes ago, George said: It's usually just 4x1" planks, double nailed and lapped to the underside of the trusses. https://nhbc-standards.co.uk/7-roofs/7-2-pitched-roofs/7-2-9-bracing-for-trussed-rafter-roofs/ https://www.tra.org.uk/download/2572/ Thanks George! Actually quite excited to do this! Link to comment Share on other sites More sharing options...
Gus Potter Posted May 8 Share Posted May 8 On 06/05/2024 at 18:55, Broughs8286 said: The rafters in our loft have been sistered on one side before us and the previous owners. When we design prefabricated roof trusses we sometimes use a thing called a "superchord" which is basically a sistering thing which strengthens the rafter locally. If you look at the stamping on the timber main truss rafter in the photo copied below, the web, rafter and sistering.. all have similar markings in terms of print colour and text layout. What you see may be part of the original truss. The timber use for a trussed rafter in the UK is not that available "off the shelf".. usually a UK truss timber grade is TR26. Thus it's not a common timber that you would use to alter a roof. It may well be that what you see (sistering each side of the rafters) is part of the original truss and that could be assocaited with say an extended eaves or a series of point loads say from another roof framing into it as other have mentioned I would go back an look carefully at the timber stamping and the eaves detail etc before jumping to a conclusion that says the previous owners have been mucking about with it. 1 Link to comment Share on other sites More sharing options...
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