George

Purlins are integral the the roof structure and often form part of the restraint to gable walls. In a king truss roof they will be halving the span for the rafters. In a word - 'very'.

While I appreciate the intention, this would fall foul of Building Regulations due to a lack of insulation. I am not convinced that breathability is important for floors. The primary cause of damp problems sounds like the external ground level. I would install an insulated slab and lay tiles onto this. If you are concerned about breathability of the floor, you could look at a limecrete floor with foam glass aggregate. These can be made to comply with Building Regulations. In my house I did used a layer of foam glass aggregate (glaspor or similar), before laying a DPM + conventional insulation. This way, there is a capillary break below the DPM, which should reduce any moisture 'moving' towards the base of the walls. However, in hindsight I think this was not necessary. The mechanical ventilation system you are installing will mean you won't get any damp issues anyway.

Another vote against concealed RWPs/syphonic/chains/dispersers. Centre them on the windows, use aluminium/copper/imitation cast iron etc. and you'll look at them once when they're put up then never look at them again.

Ah, de-stoning. Many a farming child has shifted a few tonnes of cobbles.

I think their concerns are misplaced. As long as buildings can pay for themselves and perform well within their intended design life, you're best off stopping there, else you risk over specifying and using resources better placed elsewhere. There's a cost (financial and environmental) involved if you end up over designing. There are as many reasons to demolish, dismantle or otherwise mess around with buildings as there are putting them up in the first place! Still, there are plenty of good reasons to switch steel for something else.

I stand corrected. I'm the wrong type of engineer and clearly I missed the first step when I looked into why my ASHP was 'inverter driven'. So is it AC(50Hz) -> rectifier -> DC -> inverter -> AC(variable) inside the ASHP?

I've got nothing to add, but just wanted to say this is a really interesting technology and fair play for using it. When they say basalt I assume it's essentially glass fibre but using mineral sources instead of glass. The basalt is just a marketing spin (quick google - yes this is the case). However, I'm afraid to say that your concrete will still crack somewhere after 50 years. But that's OK... nothing lasts forever. And there's only two types of concrete... concrete that has cracked and concrete that is going to crack.

For the benefit of anyone who doesn't know why it's called an inverter controlled ASHP... An inverter takes the AC mains electricity and transforms it to DC (by inverting half the polarised AC electricity to a constant DC). DC motors (i.e. the compressor, fan and pumps) can be controlled variably, which is why they can be scaled to match demand. AC motors can't do that.

The builder should have known. Hoarding licences are a very common requirement and his competitors have to be doing the same thing.

I've mine set at 50 degrees which is plenty hot enough! With the RHI grant I think you're mad not to go for ASHP but each to their own. What I would definitely recommend is design all emitters (UFH + rads) to run at a low flow temperature, so that you can just plonk in a ASHP in future. Of course, if you run a gas boiler at 50 degrees you get the full benefit of the condenser so will use less gas now. People who run their condensing gas boilers at 65+ degrees lose any efficiency advantage and just wasted money on condensing unit.

I would phone Sika as they should have a product suitable. It might be worth asking the glulam supplier as well.

Well you say that, but all your questions are the more detailed information over and above load/span tables which a structural engineer will help you with. If building control ask for calculations of the fixings you have used, what will you tell them? Buildhub 'said it would be OK'?

" will it cause a problem as they may consider that I am thermally changing the external walls and insist that I hit the renovation U Value targets? " There are two main get outs for lower u-values (can't remember the references) Most importantly is that the insulation shouldn't degrade the structure. So for an old solid wall house, a breathable insulation is suitable and you don't want too low a u-value because it will move the dew point much further inside. However.... they may want some sort of evidence (I got emails from the supplier). Second get out is 15 year pay back is needed. However this is a bit tricky to justify if you are putting insulation on the wall. That said... I didn't tell BC. Just got them to approve the extension works.

Hello, I've had my Samsung Gen6 ASHP running well since November last year. Very happy with it. However looking at the controller, there 'energy generation' figure is waaay higher than the energy consumed. It would work out as COP of 6-12! I've checked the consumption figure vs the separate meter on the fusebox and that it broadly in agreement. Does anyone know what sensors or calculations are used to calculate the energy generation so I can troubleshoot a bit further?

I think you would be wiser to keep as much of the building as possible. There are some horror stories about enforcement when demo has gone too far. That said, ANY doubt or concerns about the stability of the wall, get a suitable qualified temporary works engineer involved. They weigh tonnes and you do not want it coming down on anyone.

Yeah you need that foundation. It could be made smaller but unless you have unusually large footings you'll often find it's more hassle than it's worth. You need a short section of wall to come up to near FFL for the door cill to sit on and to act as an edge for the underslab insulation and slab edge itself. You could achieve this with formwork etc but it's a much messier detail overall (espeically for DPM/DPC) and better to have the ~450mm wall up from the footings. On my 3m bifold opening I stopped the innerleaf blockwork and just have the outerleaf brick for the cill and slab edge. It wasn't a typical detail but close enough. You architect should have this type of detail on a building regs drawing. (structurally it is better for the slab to be isolated from the walls. Unless it's designed as a raft this is the best approach)

Normally you'd build the RC wall first with formwork and use stainless steel frame cramp type ties into the concrete. Are you intending to use the brick/block as a permanent formwork? You will need to support the wall as the lateral force from the concrete would potentially burst the wall. I think you need to go back tot he designer and ask them how they intended for this to be constructed.

These are all questions you need to put to a structural engineer. There are other variables that need to be taken into consideration.

Living there will be a nightmare but the structural changes aren't too alarming. You will need a suitably skilled builder as, especially with the phasing for weathertightness, it needs to be planned well.

Wrapping joist ends with DPM is a common solution. It is worth mentioning that all timber will rot in humid conditions - you must improve the subfloor ventilation (air bricks and gaps in sleeper walls).

I admit I didn't get too much further and won't unless I get a job to design one...! As far as I can make out, the underlying assumption is that if ICF is treated geometrically like masonry, it will be fine! That is, using geometric rules, return walls etc. That is a reasonable approach as you can build perfectly good sized houses from masonry and is fairly conservative anyway. Like you say, it is the interfaces and connections that need special attention.

It is, but relatively minor. I don't think this would cause issues for building regulations or anything short of a passivhaus. The balance an architect needs to strike is the building regulations, what a builder can build (i.e. what are they used to), cost and what they know works. I've seen a lot worse and with 200mm PIR the average U-value of the wall will be very low. With an internal VCL I don't think condensation will be an issue. Question the architect, if I had to mitigate it with minimal changes I'd change what the sole plate is sitting on to a course of thermoblocks.

Two issues spring to mind: 1 - strength of the crate is intended in the correct orientation (and adding extra holes won't help) 2 - if the soffit level is too high it'll reduce the storage capacity May not be a problem but potentially is. Phoning the manufacturer is usually the safest way.

For what reason do you want that information? You need to address valid complaints, otherwise ignore. There is no need for you to know where they live.

Yeah don't worry. Spent 4 months insulating... but as its locally listed all internal wall using wood fibre so never going to meet passiv haus type performance. However electric heat pump heating is a fraction of what oil used to be and that only effectively heated one room.