rcast1989 Posted July 26, 2023 Author Share Posted July 26, 2023 (edited) 2 hours ago, Iceverge said: I've had a quick scan of your plans. Your architect has made the walls very thin. Maybe 300mm? You might struggle to get to BRegs with this. Have you robust details for the parapet walls and flat roof. These need to be bomb proof. Especially with timberframe. Thanks for the help Does this assist? 20-004 Rev B - As Proposed Construction Sections (1).pdf Structural Engineer 18.3693.002A ( Ground Floor Structural Layout & Details ).pdf Edited July 26, 2023 by rcast1989 addition of file Link to comment Share on other sites More sharing options...
Iceverge Posted July 26, 2023 Share Posted July 26, 2023 Ah bugger..................... Another Architect who has been taken out for lunch by the Kingspan salesman, shoved a little book with nice copy and paste details and told " this will solve all your problems". They've left you with an expensive option and a non compliant U value ( unless you magically stop all air infiltration and convection inside the unventilated layers of air in the wall build-up). I've written another post on this. Here's a quick calculation of the wall as proposed. It'll be worse in reality as the Kooltherm boards will certainly not be sealed 100% to the timbers and you'll get thermal looping (moving air inside the wall). They're very thin also at 285mm. Architects tend to be very good at concept, usability and balance of designs but alas many fall down on the practicalities of actually building a house. I know this isn't what you want to hear but I'd be tempted to fix the design into something better on paper now before going any further down the building route. Go for thicker walls and make sure all the structure is covered by a pitched roof, balcony included. Get rid of the parapet walls and the bay window. They're going to leak water and air and heat long term. Ensure that no element of the house cannot be easily brought in on a flatbed trailer and can be lifted into place without any large equipment. Sorry if I'm being a killjoy but it annoys me to see professionals being so careless with their customers money. Do you have planning permission yet? 4 Link to comment Share on other sites More sharing options...
saveasteading Posted July 26, 2023 Share Posted July 26, 2023 That is pretty much what we have done. We are adding an insulating layer on the inside to achieve current standards, and it will also reduce temperature fluctuations in the service void. We have modified our wall cavity design to be 50% pir and 50% (ish) mineral wool. Practical and more likely to perform as intended. I've not seen a technical assessment on thermal looping in this situation. I know it is an issue in windows and especially skylights. In this situation I'm not immediately concerned , but happy to be enlightened. @IcevergeSo right about the Kingspan details. Their manuals used to be so good that it was often my first reference. Then they give the free cad stuff to architects so no thinking was required. As I've said, I have not looked at the drawings. Is this based on the ubiquitous Scottish white hoose? 1 Link to comment Share on other sites More sharing options...
rcast1989 Posted July 26, 2023 Author Share Posted July 26, 2023 1 hour ago, Iceverge said: Ah bugger..................... Another Architect who has been taken out for lunch by the Kingspan salesman, shoved a little book with nice copy and paste details and told " this will solve all your problems". They've left you with an expensive option and a non compliant U value ( unless you magically stop all air infiltration and convection inside the unventilated layers of air in the wall build-up). I've written another post on this. Here's a quick calculation of the wall as proposed. It'll be worse in reality as the Kooltherm boards will certainly not be sealed 100% to the timbers and you'll get thermal looping (moving air inside the wall). They're very thin also at 285mm. Architects tend to be very good at concept, usability and balance of designs but alas many fall down on the practicalities of actually building a house. I know this isn't what you want to hear but I'd be tempted to fix the design into something better on paper now before going any further down the building route. Go for thicker walls and make sure all the structure is covered by a pitched roof, balcony included. Get rid of the parapet walls and the bay window. They're going to leak water and air and heat long term. Ensure that no element of the house cannot be easily brought in on a flatbed trailer and can be lifted into place without any large equipment. Sorry if I'm being a killjoy but it annoys me to see professionals being so careless with their customers money. Do you have planning permission yet? Thats so helpful and disappointing at the same time, we really had a lot of trust in our architects to guide us as they have been involved with the project for so long (we bought it as a plot with expired planning) The planning is now fully approved once again but there are now tighter building regs in Scotland that came out earlier this year. Maybe this will have an effect on the wall make up. We are also using a different SE compared to the drawings (these are previous work from he previous build warrant application) At least that allows me to go back and question these aspects Link to comment Share on other sites More sharing options...
rcast1989 Posted July 26, 2023 Author Share Posted July 26, 2023 1 hour ago, saveasteading said: That is pretty much what we have done. We are adding an insulating layer on the inside to achieve current standards, and it will also reduce temperature fluctuations in the service void. We have modified our wall cavity design to be 50% pir and 50% (ish) mineral wool. Practical and more likely to perform as intended. I've not seen a technical assessment on thermal looping in this situation. I know it is an issue in windows and especially skylights. In this situation I'm not immediately concerned , but happy to be enlightened. @IcevergeSo right about the Kingspan details. Their manuals used to be so good that it was often my first reference. Then they give the free cad stuff to architects so no thinking was required. As I've said, I have not looked at the drawings. Is this based on the ubiquitous Scottish white hoose? no where near it unfortunately bespoke build over the edge of a burn Link to comment Share on other sites More sharing options...
Iceverge Posted July 26, 2023 Share Posted July 26, 2023 1 hour ago, saveasteading said: I've said, I have not looked at the drawings. Is this based on the ubiquitous Scottish white hoose? I would say it is a variation of the long house but with some sticky out bits that have parapets and flat roofs. Fine in the Santorini with 340mm of precipitation but in western Scotland with 1500mm of rain annually I think it's asking for trouble. Here is the ground floor suggested build up. The U value at a guesstimate is 0.4W/m2K. Link to comment Share on other sites More sharing options...
Dreadnaught Posted July 26, 2023 Share Posted July 26, 2023 My tuppence worth. I agree with @kommando. I have restricted access, albeit only 80 metres worth. And could not have a crane on site too. My frame builder, which I chose to be local, simply had the frame designer design smaller panels, which were made in the factory and brought to site on a smaller lorry and then handballed in to position with dollies and few burly lads. It went up easily. 2 Link to comment Share on other sites More sharing options...
eandg Posted July 26, 2023 Share Posted July 26, 2023 On 25/07/2023 at 18:00, rcast1989 said: Very much looking forward to seeking all the help and advice required of a young couple taking the plunge into our first family home ( and self-build). We have a lovely plot on Clydebank, Glasgow but it is drought with obstacles for modern-day options such as SIPS, modular and timber kit, namely access! The local lane is very narrow and despite going to some of the big names ( fleming homes etc.) the SIPS/timber kits would be too wide to easily get through the lane which is 9 feet wide at its worst. The feedback has been we will need to complete a "stick build" and know now what that is but can't seem to find anyone local that does residential. We have an architect, we have an SE but contractors, suppliers, fitters, "stick builders" all goes way over my head and really need a project manager or a contractor to go through from start to finish. Any help or recommendations much appreciated! PS I will put this in correct forum once open! I can recommend and put you in touch with a firm local joiners - yard is in Drumchapel and all the boys are north west Glasgow. They've done some framing and sheeting work for me but also act as main contractors and do a lot of bigger commercial jobs (and are registered with Federation of Master Builders). Link to comment Share on other sites More sharing options...
rcast1989 Posted July 26, 2023 Author Share Posted July 26, 2023 1 minute ago, eandg said: I can recommend and put you in touch with a firm local joiners - yard is in Drumchapel and all the boys are north west Glasgow. They've done some framing and sheeting work for me but also act as main contractors and do a lot of bigger commercial jobs (and are registered with Federation of Master Builders). That's exactly what we need mate, local decent knowledge and guidance, it would really be appreciated. As others mentioned we probably put too much faith in our architects not even thinking they could be designing a house that is buildable! Hoping a good contractor, non material changes and a definitive build type will bring project to fruition Link to comment Share on other sites More sharing options...
saveasteading Posted July 26, 2023 Share Posted July 26, 2023 That is very pretty. i could cut and paste from my standard responses! where are the rainwater pipes? Glasgow has the second largest amount of rainfall for a town or city, but has the highest number of wet days with 14.2 on average every month. Actually that is possibly less onerous than London and other places with less rain but in huge downpours in recent years. do you like that wall colour? If you intend it to go grey then show it grey. if you want to keep it that colour you must apply a finish. the horizontal boarding will catch the water at every joint and go slimy unless this is looked at in detail. That roof needs a very good builder indeed. I see from the ground floor construction that you will be running 5 tonne forklifts. You might want to tell your people to try harder, or are they subsidising it? 90mm pir (kingspan again) is not nearly enough. Plus the floor is the easiest area to insulate so more here can offset the walls as they are. some confusing description of the floor, but seems upside down. then over the industrial slab you have a batten support system and then chipboard. I feel I have missed something. Either that or it is a good time to change designer. 1 Link to comment Share on other sites More sharing options...
rcast1989 Posted July 26, 2023 Author Share Posted July 26, 2023 (edited) 4 minutes ago, saveasteading said: That is very pretty. i could cut and paste from my standard responses! where are the rainwater pipes? Glasgow has the second largest amount of rainfall for a town or city, but has the highest number of wet days with 14.2 on average every month. Actually that is possibly less onerous than London and other places with less rain but in huge downpours in recent years. do you like that wall colour? If you intend it to go grey then show it grey. if you want to keep it that colour you must apply a finish. the horizontal boarding will catch the water at every joint and go slimy unless this is looked at in detail. That roof needs a very good builder indeed. I see from the ground floor construction that you will be running 5 tonne forklifts. You might want to tell your people to try harder, or are they subsidising it? 90mm pir (kingspan again) is not nearly enough. Plus the floor is the easiest area to insulate so more here can offset the walls as they are. some confusing description of the floor, but seems upside down. then over the industrial slab you have a batten support system and then chipboard. I feel I have missed something. Either that or it is a good time to change designer. I will give them the benefit of the doubt until I see the SE input with regard to the rainfall, there are definitely changes to be made! these SE drawings are outdated with a different firm so hopefully our new SE will have a much better grasp on the requirements living in "sunny Glasgow" Does mean I have to admit defeat and say my wife was right when she wanted all of the flat roofs to be an extension of the pitched roof and wanted the balcony covered XD Edited July 26, 2023 by rcast1989 Link to comment Share on other sites More sharing options...
rcast1989 Posted July 26, 2023 Author Share Posted July 26, 2023 6 minutes ago, saveasteading said: That is very pretty. i could cut and paste from my standard responses! where are the rainwater pipes? Glasgow has the second largest amount of rainfall for a town or city, but has the highest number of wet days with 14.2 on average every month. Actually that is possibly less onerous than London and other places with less rain but in huge downpours in recent years. do you like that wall colour? If you intend it to go grey then show it grey. if you want to keep it that colour you must apply a finish. the horizontal boarding will catch the water at every joint and go slimy unless this is looked at in detail. That roof needs a very good builder indeed. I see from the ground floor construction that you will be running 5 tonne forklifts. You might want to tell your people to try harder, or are they subsidising it? 90mm pir (kingspan again) is not nearly enough. Plus the floor is the easiest area to insulate so more here can offset the walls as they are. some confusing description of the floor, but seems upside down. then over the industrial slab you have a batten support system and then chipboard. I feel I have missed something. Either that or it is a good time to change designer. The photos were just an "artist's impression of what it could look like, all finishes and exterior yet to be decided which I am very glad about considering the great feedback from members Link to comment Share on other sites More sharing options...
saveasteading Posted July 26, 2023 Share Posted July 26, 2023 37 minutes ago, rcast1989 said: bespoke build over the edge of a burn a la Frank Lloyd Wright. (Waterfalls) . Is that wise? The SE doesn't do down-pipes. if external they should be shown on the drawing so you know what it really looks like. They may have to check the gutter size though. If internal....no please don't, they may leak and they will gurgle. seriously about the slab. 150mm reinforced concrete is an industrial slab for forklifts and racking. Then you have have battens and chipboard????? I advise do not give any 'benefit of the doubt'. You will pay for then live in this house. Now is the time to insist on a practical design that will be to your budget. you have an economic wall construction, tho needs changes made, a very expensive roof, and an over-designed floor. Allow lots of money...you have discussed budget I hope. Have you checked your consultants out? seen examples? They may be qualified but this not really be their thing. Or the alternative is to not have an architect as a good (and substantial) builder can make this work. Then the SE signs the papers. 1 Link to comment Share on other sites More sharing options...
Dreadnaught Posted July 26, 2023 Share Posted July 26, 2023 More tuppence. If you go the timber-frame route, make friends with your frame designer. He will have a wealth of knowledge about what's buildable and how to make the frame simpler. Don't fall for the mistake of letting the frame designer deal only with your builder or frame manufacturing company. Your builder may sign the contract with the designer and may well pay his bill at the end of the day, but you should have long discussions with the designer yourself both so that you can learn and that your priorities will end up being incorporated in the frame design. This is what I did. If I build another house (and I may), I will change the process. I will first choose and retain a frame designer myself (probably the same one as I used this time as we got on well) and design the dwelling with him (plus an architect for the aesthetic input). And then take the design to a timber frame manufacturer to make and install it all on site. Link to comment Share on other sites More sharing options...
Thorfun Posted July 26, 2023 Share Posted July 26, 2023 +1 on all that's been said about wall widths, insulation levels etc. I think you need to specify a U-value target for the architect to achieve WITHOUT using overpriced Kingspan Kooltherm products but standard insulating materials. we have 140mm Frametherm 32 (it's actually Isover but it's a bit like PIR being called Celotex) between our 140mm TF studs and 80mm PIR internal to that for the walls. for the roofs we have 190mm Frametherm 32 and 100mm PIR internally. under the slab we have 300mm EPS. some might say excessive but this is what we wanted to get right from the off. you could also investigate a twin-wall TF (which can also be stick built) with blown in 300mm cellulose. many on here have that make up and say great things about it although there are some naysayers on here about it sagging and drooping but you can't always believe them. 😉 get the insulation AND airtightness done right and enjoy lower running costs for the rest of your lives there. ps. spend weeks and weeks reading on here on the relevant sub-forums and then go back to your designer armed with ammunition about what YOU want, not what they want to churn out for you. Fabric first should be your mantra. good luck! I like the look of the house 1 Link to comment Share on other sites More sharing options...
Iceverge Posted July 26, 2023 Share Posted July 26, 2023 3 hours ago, rcast1989 said: Does mean I have to admit defeat and say my wife was right when she wanted all of the flat roofs to be an extension of the pitched roof and wanted the balcony covered Yup! Have a look at the way these guys do roofs. Nowhere for a leaf to get caught and the walls are super protected from the rain. https://www.makar.co.uk/portfolio Also I think you're missing a trick by not having carport access to the house under cover. We didn't and it's a regular sprint thought the rain with the kids to the car. 1 Link to comment Share on other sites More sharing options...
saveasteading Posted July 26, 2023 Share Posted July 26, 2023 Our decision has been to use 50mm pir cut in slabs and pushed between studs, then the rest filled with frametherm. The reasons follow having done the initial phase and found the difficulties, and with much reading and advice on BH. We initially had 100mm pir. To get that cut to the right size is tricky, and you can't assume the spaces are standard or exactly square. so it involves squeezing into the space and some gaps. With 50mm all aspects are verymuch easier and more precise. Then the frametherm can be pushed into the remaining space, filling every gap. So as much pir as reasonably practicable, for the insulation value. then frametherrm with lower insulation, but totally closing air gaps. This does not meet regs. (We don't have to for a conversion, but are aiming for new-build standards because we can. Any shortfall can be offset by additional insulation elsewhere.) Inside the stud walls we are leaving a service gap (much appreciated by the electrician..in fact it might have convinced him we would be a good client. Then the inner wall will receive either insulated plasterboard, or fibre-board, yet to be decided. Link to comment Share on other sites More sharing options...
Dave Jones Posted July 27, 2023 Share Posted July 27, 2023 7 hours ago, saveasteading said: Our decision has been to use 50mm pir cut in slabs and pushed between studs, then the rest filled with frametherm. The reasons follow having done the initial phase and found the difficulties, and with much reading and advice on BH. We initially had 100mm pir. To get that cut to the right size is tricky, and you can't assume the spaces are standard or exactly square. so it involves squeezing into the space and some gaps. With 50mm all aspects are verymuch easier and more precise. Then the frametherm can be pushed into the remaining space, filling every gap. So as much pir as reasonably practicable, for the insulation value. then frametherrm with lower insulation, but totally closing air gaps. This does not meet regs. (We don't have to for a conversion, but are aiming for new-build standards because we can. Any shortfall can be offset by additional insulation elsewhere.) Inside the stud walls we are leaving a service gap (much appreciated by the electrician..in fact it might have convinced him we would be a good client. Then the inner wall will receive either insulated plasterboard, or fibre-board, yet to be decided. cut studs to 400 gaps not centres to remove waste from celotex sheets. Gapotape the insulation. It's like compriband for insulation. really good stuff. Link to comment Share on other sites More sharing options...
ProDave Posted July 27, 2023 Share Posted July 27, 2023 2 hours ago, Dave Jones said: cut studs to 400 gaps not centres to remove waste from celotex sheets. Gapotape the insulation. It's like compriband for insulation. really good stuff. Then you end up with stud spacing that does not match plasterboard sheet sizes, setting yourself an other problem to solve. Link to comment Share on other sites More sharing options...
eandg Posted July 27, 2023 Share Posted July 27, 2023 1 hour ago, ProDave said: Then you end up with stud spacing that does not match plasterboard sheet sizes, setting yourself an other problem to solve. And less insulation in the walls? Link to comment Share on other sites More sharing options...
Iceverge Posted July 27, 2023 Share Posted July 27, 2023 I would use mineral wool between the studs. (As a second to blown cellulose) Almost zero waste,all offcuts can be tucked in somewhere. It can move with the timber as it expands and contracts. Better for fire protection, sound protection, decrement delay. Easy and fast to fit well. Get a bread knife and cut it slightly large and it tucks in perfectly. For a 140mm stud wall with a continuous internal of PIR like @Thorfun just bump that layer by 10mm and you are at the same U value. @saveasteading did you consider Using something like a mineral wool full fill batt and a 22mm insulated plasterboard for less labour overall? 1 Link to comment Share on other sites More sharing options...
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