Bonner

Standard flexies are suitable for the vast majority of mains pressure installations. You will be fine with 10mm unless it is a really long run (pressure loss is a function of pipe diameter and length).

+1, ties not needed. Rafters are fixed to the wall plate which is fixed to studs, all skinned with ply ... it’s not going to blow away! ps, looks cosy already ?

... or waiting for a freezing cold day ⛄️

Just an update to this thread in case it helps anyone else in a similar situation ... To get the wall plate to sit low over the windows, SE approved a 65mm concrete lintel over the cavity wall lintel (1250mm opening). For the 3m opening, we had to get a steel beam made with extended bottom flange to carry the wall plate. The truss manufacturer agreed that the builder can trim as shown and screw plywood plates both sides. Quite a simple solution in the end but a few sleepless nights as a result of poor communication and lack of diligence in checking things.

Make it permeable, block paving or similar. Otherwise you will need a soak away of some sort. As a rough comparison, my garage is 45sqm which needs a 2cu.m soak away.

Northern Powergrid initially quoted me a 3 phase connection for a few hundred £ more than single. When it came to formal quotation after survey, the network needed upgrading at a cost of £15k! I settled for single phase as it is unnecessary for most homes anyway. Plenty of single phase 16kW ASHP’s available, if you really need that size. Two units would be excessive, talk to other suppliers.

Standard opening is 910*2100 which would match the door size you quoted. I would be more generous for a front door.

RHI will pay me 10k over seven years ... if I can get it installed in time. Key question for me, is MCS required for this grant?

Technically, it will work but significant change from the planning drawings, don’t think this will get through a NMA

7 windows, 4 at the front and 3 at the back. Unfortunately only one pair line up front to back so doubling up the trusses either side will be difficult.

All the windows are 1250mm wide except a 3m wide double height opening which could be treated differently. That might work! When you mention an upstand or dormer do you mean lowered trusses (and ceiling) either side of the windows? We want to avoid changing the roofline if possible...

Completely agree, nothing will be changed without calcs from the truss manufacturer

The design had tall windows with the roof sitting low over them, a barn like concept. Since we cannot raise the eaves, reducing the window height is the most likely compromise. I am not worried about the window size but it will change the look quite significantly. As mentioned, if I knew about this earlier I would have gone back to the drawing board with the design.

Well I think we have a solution for that issue, SE has agreed concrete lintel over the That is for the single storey living room, However it gets worse on the main roof ... This is the eaves detail, similar to the single storey but trusses here with raised tie (3.3m first floor ceilings) That is the drawing sent to the truss manufacturer and this is what they made ... No prizes for spotting the difference - chord depth 365mm compared to 210mm on the drawing, also 200mm wide foot will have to sit over the lintel not behind it. Consequence would be 6-7 courses of brick over the windows rather than one course shown. Having spoken to all parties involved on Friday, what happened is : Architect designed something that is difficult / impossible to build, but they argue their drawings are ‘representative’ and must be checked by truss manufacturer or SE. Truss manufacturer are admitting they had the drawings but cannot make anything to fit and told the builder this. Builder ordered them without coming back to me or architect So what happens now ... Truss manufacturers are looking how these can be modified to at least get them lower (3 courses of bricks over the window head would be acceptable, 6-7 course is a major design change) Architect is looking for construction details of similar designs they have done in the past. Builder is busy avoiding any responsibility and blaming everyone else I am prepared to compromise (so far) because it seems the original concept was just that, would have to be modified at some point. Also, the build is dragging on far to long and we don’t want any further delays. It would have been so much better if this was recognised earlier, we could have adapted the design without much drama. Thanks for reading this sorry story and let it be a lesson for others as it has been for me Any ideas for a solution would be highly welcome!

When you say sash windows, are they sliding sashes? These can be challenging to seal effectively, even modern ones. Also an 8mm air gap in double glazing is very weak by modern standards.

I used a fibreglass cabinet like this, with 12mm ply back board https://www.ebay.co.uk/itm/273799954572?mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338781477&toolid=10029&customid=EAIaIQobChMIzOTntou08wIVkM13Ch3PMA70EAQYGSABEgKdbfD_BwE&_trkparms=ispr%3D1&amdata=enc%3A1IYqadMMeS7WqSSjMKFclqQ6

Thanks everyone, I will share the outcome of discussions with BCO/SE when we have agreed a solution.

Cheers Peter, we have agreed to check with BCO and the SE if necessary. Slightly surprised this detail was drawn by the architect and approved by BC but I am sure we will find a solution.

Yes, big glulam ridge beam and cut rafters, calcs done by the truss supplier so should not see significant horizontal load.

Not sure what you mean by a composite lintel, these are standard steel Catnic cavity wall lintels. I looked on the Catnic website but couldn’t see any specific guidance but IG site mentions minimum 150mm of masonry.

That certainly makes sense but it depends how that weight is distributed. The architect has shown quite a thick wall plate, presumably to distribute the load ...

Thanks @tonyshouse, apologies I should have said the lintels are already in. Take your point about thermal bridging so will see if they can replaced. If not, is it acceptable for the wall plate to sit directly on a lintel without a course of masonry?

Is this a standard construction detail? The builder is saying it is necessary to put masonry on the lintel before the wall plate but that will raise the eaves and ridge height. If masonry is not needed should he just bed the wall plate on the lintel with mortar?

I got a quote from GBS for Alu-clad and timber, they tried to push me away from Alu-clad for environmental reasons. Thought that was a weak argument considering the quantity of material and not consistent with what they are saying now.

That’s interesting, sounds like it’s carbon neutral ? ... on that note, I’ll get my coat ....