Owain1602

You are right @Gus Potter, that Protek on the Structural Warranty outsource the inspections and responsibility to another smaller firm. But the smaller company are controlled massively by Protek, and ultimately, it’s Protek that decide if they are happy with the evidence submitted to Surveyor Link. I had one instance where the smaller surveyor company weren’t sure what to do regarding a retrospective watching brief on excavations. They gave me the details and asked me to call the main man at Protek. Explained the situation to him, and he was happy. He told the smaller firm to accept my explanation, and we moved on. Coming back to the original question regarding build insurance, do you also have liability in the policy? As I say, we went around the houses with numerous other companies. Protek were the simplest to deal with (although quotes for rebuild costs over £1M took a long time!). We went with a price very similar to yours for 15 months cover. FYI, Protek are not the insurer, it’s a company called QBE

We had/have the same situation. Anything over £1M goes down a different pathway in these companies, and gets a more bespoke assessment. I found that the costs go up disproportionately for anything over £1M. Went with Protek in the end, after looking at others. @Gus Potter You seem to be discussing warranty, whereas the question is related to insurance.

We have just gone through this. As @ETC says, easiest thing in most cases is to put in a Radon membrane (Visqueen R400) and sometimes a sump (Damplas one was £50). Insulated raft foundation engineers included full Radon protection in their foundation drawings (as we’re in a high area). Building inspector and structural warranty inspector was all over the details like a rash. Wanted images to show the sump had been installed, gas tight joints on all pipework to the sump. Spent a while inspecting the R400 membrane joints, laps, and in particular the penetrations. We had top hats on most (which must also need a Jubilee clip to secure), but some more complex ones needed a specific Visqueen detailing strip, which is a sticky butyl backing with a thin layer of Aluminium. They also insisted the Radon membrane projects at least 1m out from the walls of the house (under ground obviously). Not much more hassle than using a DPM if done at the right time.

With all due respect, I don’t think you should be giving any advice. Just because you’re not comfortable to be operating an excavator and dumper around some block work. If you don’t trust yourself, get an experienced operator, or get the bulk of the material well away from the blocks out with machinery, then pick away at the rest by hand. It sounds to me like you should be spending more time doing things, rather than getting every opinion under the sun about how something should be done. Why was the material not excavated before the blocks started going in? No idea the footprint of what you’re doing, but I can’t imagine it would be more than a day of work. Did you ask the guy doing the blocks if you could delay him by a day?

I see you’ve written that your CIL liability form was “approved”. Do you mean that you’ve signed to confirm you accept the CIL liability (which you must do first)? Or you have had your CIL exemption confirmed? Also, do you have any pre-commencement conditions on your planning approval?

Did you have a contract of sorts in place with clear scope/deliverables? Then, did you request any changes/deviations to the deliverables agreed in the original agreement, and were these formally documented? You can work with people/companies in many different ways, but you need to tailor your approach to suit the framework that’s in place.

The planning authorities I’ve had dealings with had Consultation as Stage 4 and then Site Inspection as Stage 5 (total of 10 stages). In most cases, they don’t feel the need for a site inspection, but they would want to factor anything raised during consultation in their site visit. I don’t have experience of extending an existing property, but if CIL is a potential, then you need to be very careful.

Hello all, I’m currently in the process of preparing ground for an 8x8m steel frame workshop. The area currently has a 1m elevation change from one end to the other. I’m digging in to the bank on the high side, planning on getting a level pad at the height of the current lowest point. Obviously I needed to remove material from the current lowest elevation to remove the topsoil etc, before filling this back in with suitable aggregate. As I’m digging in to the bank to level the ground, I noticed the material coming out looks surprisingly similar to the material I’d be buying in to raise the ground at the lower side. My question is, do you think this material is suitable to bring the levels up (see image below)? I would be using MOT or similar as the final layer under the concrete slab. It’s all dug out and 10m away from where I’d need it. I would lay it in 150mm layers and bring in a heavy plate compactor or even a roller if needed. Workshop will be steel frame, 1m3 concrete stanchion under each steel, with 200mm C35 slab encasing the steels, A252 mesh. As further background for those interested. The site is at the highest elevation in the area, and is predominantly sand and sandstone from about 150mm down. We’ve had a Geotechnical ground survey for our house foundations (approx 40m away), and the ground has >150kPa bearing pressure from 500mm down according to the report. Thanks for any advice!

My experience is that timber frame is considered standard construction by the mainstream lenders. What they really don’t like is more than 50% timber cladding. You can find the lending criteria documents for most banks online, which gives a high level overview of their policies on various topics. Some banks have a “special” part of the website for mortgage brokers/intermediates, where they provide these document. Google is your friend here, as a lot of them make it tricky to find the lending criteria from navigating their main site.

Do you know which building heat loss calculations use convective boundary conditions on the internal and external walls? The simplified spreadsheets that I've seen most use just imposes the temperature on the surfaces of the internal and external walls. You can see in the example values above, accounting for the convective boundary on a single slice of the tank reduced the heat loss by ~10%. When I look at the results of this, the external surface of the tank for the top slice was actually at 22°C (for an ambient temperature of 18°C). I will have a look at the relative magnitude of this effect on a section of wall later this evening, to get an idea if it's significant.

Then, the second point is a bit more interesting and something I'm not sure is being factored in to a lot of house heat loss calculations (not suggesting it's a big impact, haven't looked at it in the context of houses). The external wall of the insulation will not be fixed at the ambient room temperature (18°C as you have it in your example). This should be a convective boundary condition. The formal definition is a Neumann boundary condition, as opposed to a Dirichlet (imposed temperature). Where I think this could be interesting, is that the whole house heat loss calculations I've come across, assume the surface of the internal walls are at the internal temperature and vice versa for the external walls. In reality, you have a heat balance for the wall, with a convective boundary condition on either side. The top "slice" of the tank in the original example lost 4.04W Adopting the 1D heat equation in cylindrical coordinates reduced this to 3.39W Changing the external boundary condition at the wall of the cylinder from a fixed 18°C to an ambient temperature of 18°C with a convective heat transfer coefficient of 5W/m2K reduced the loss to 2.98W (already includes impact of different formulation) Would be interesting to apply this approach to the heat loss of a whole house (obviously not including the cylindrical coordinate system, unless it's a very unusual shape!)

Hello @SteamyTea You should be using the 1D heat equation derived for a cylindrical coordinate system for the heat loss calcs. It's not a night and day impact (depends on the geometry), but I get just under 10% higher heat loss using this approach.

Thank you all, we’ll have a look around for a different architect to work with.

Agree with what? I am not following any advice posted here for building regs, the approach to protect the stairway I outlined above was put forward by our architect.

Hm…that’s not a good start, nobody has spoken or used them for their build?