saveasteading

Then you are blocking the ditch. A bad thing. Am I misunderstanding?

Sips is trendy. Sips is limiting re geometry. Use what the local builders are happy with, whether timber frame or masonry. Or buy in a timber frame as a kit. TF is not expensive if kept simple.

Once you have had the word used, you need to advise insurers for ever, so it's a good thing the term is not used here. As the structure is OK, it probably isn't. You have a small chance of a big problem. Ultra local moisture effects are unlikely......the slab is protected by walls and footings. A large chance of a small problem. Tell us more about the hollow sound. Is it when walking, or tapping? Could there be a top screed that is loose after pipes were cut in?

It is meant to cling to surfaces to allow bacteria to do their stuff. As you say, we don't know the circumstances. But the cover levels are +/- a metre, so it all seems strange. Agree re using French drains rather than crates for sewage, but maybe this is for storm retention.....can't tell.

Subsidence seems the likeliest thing. Ground shrinkage would be more general than just that corner. It might only be the slab, not foundations. If it is clay shrinkage then it shoild tecover over the winter Are there any cracks in walls, inside or out?

All the worthy terms get stolen and abused by the developers. My main hate is " value engineering". It used to mean elegant, efficient construction. Then the QS industry turned it into missing things out and cutting corners. So I don't use the term any longer. My own prejudjce on "eco" is of experimental houses, spending other people's money on nth degree of detail and anything trendy. Wind turbines, ground source, off-site, green roofs, solar regardless of circumstances.

This discussion also took place a few days ago. My summary was: If you know exactly what you are doing, the building is conventional, and you accept risk. Building Notice, and you can start more quickly. Otherwise, Full Plans.

I like that. It should save cost, and take up much less space. There used to be a standard EU design but perhaps that is superseded now, or simply ignored. Plus Klargester is part of Kingspan and I wouldn’t give them £1 of my money. Agreed. I intend to look up all the Kingspan brands, also St Gobain (who have sold off celotex), and avoiding them.

The design is a mess. Sorry. Can you show more of the drawing? Digesters have waste in one end and out the other, not as shown. Non return valve?? Are the crates to hold flood water then it drains away, or as a soakaway?

That said..... I've just finished designing our own. The drainage field size is crazily large in my opinion. The regulations only allow a 20% reduction as compared to a septic tank outflow. In reality the bco may accept a soakaway. With a bit of gravel on the bottom that would work nicely....say I but it isn't my decision. FYI A Structural Engineer generally studied and got a degree in Civil Engineering. Or Civil and Structural. Thereafter there is too much to know and it is best to choose one then later take the Professional Exams. So your SE may well be a little behind on treatment tanks.....understandably as the regs are a mess. It is tempting though to go with the flow as an "SE" though, as a differentiator from groundworkers who call themselves civil engineers. As above..choose an air bubble make. I am specifying Marsh. You need a sampling chamber too. Document H, page 45 and others, if you are up for it.

The digester must have its own soakaway or drainage field. This is so that any nasty stuff that makes it through will cling to the hardcore or gravel surface and the digestion be completed. Otherwise the mucky stuff percolates down and may contaminate the aquifer or other waters.

As discussed elsewhere I've recently been knocking up such a wall. What I found was that the osb is very fragile at the perimeter, where a squint screw or a little twist will break it. But on the central stud they fix snugly, as they do on noggins and any other non perimeter surface. Then it is stiff and think the perimeter ones work well enough in shear. Glad it's all ok. It's the danger of misinterpreting a photo. There are a few options to keep the house standing. Will you keep us informed?

A worrying thought. That stud wall would need 2 more studs to be at 600cc. An extra £6. And it should have noggins. I don't think a designer or the developer decided that. Was this subbed to a little builder who put 4 studs in the wall and 2 in the van? How often do I see someone on Facebook selling a pile of stud? Why do they have it? Where did it come from?

Can you look in manholes in either direction to measure the pipe depths?

I think top entry is OK. I would be browsing through the regulations though. Building Regulations Document H. As you say, angling in the direction of flow would be good. It will reduce turbulence, hence aid flow. It also provides a little more flexibility for fixing.

About 700 miles from you, but the Crestala Fencing website shows pictures of every fitting you could imagine, and more.

It is a heavy duty cross bolt. I didn't know that: I did a search for you. Surely the big Inverness merchant will have them. You might want a "loop over" as well.

The reason I asked is: if this was a mass produced timber frame, then it is very unlikely the wall was built incorrectly. I think 900 cc is very unusual and with osb being 1200 wide the boards would be horizontal.

Was there a manual with the house? There should be, and advising what the walls are doing..... I've only seen one such and it was junk.... no useful info at all.

Im guessing a bit here. The wall is not supporting floors or an upper wall, or the studs would be closer together. But it is an important racking (anti domino effect) wall, hence the osb and should not be removed. Needs a proper assessment by an SE. Because other people have done it, doesn't make it ok. This really could fall down. Was this built as part of a big development?

But it says that is covered and we all pay towards that risk. PI will say that reasonable skill must be applied. PI is very expensive even with the qualifications and experience. I think we paid £25k (current equivalent) per annum for 30 years, and no claims.

No. Firstly he prob hasn't got PI. He is a builder not designer, as far as we know. Secondly he has not built as designed or competently. Insurer would decline and walk away.

Yes. Keep them apart.

...remedial action within a reasonable time.... it says. Perhaps you should suggest what is a reasonable time. I'd suggest you have already given notice and sufficient time for them to consider the remedy. You have now to give a target programme. So...you look forward to his formal proposal by ...date. 23rd September? Which is to include his programme for the remedial works. Failure to do this will result in omnibuswoman considering having the necessary remedial works by another contractor. You the builder will be liable for these costs, consultants and other costs arising, and also liquidated and ascertained damages caused by the delay. I hope it doesn’t come to this and look forward to receiving your constructive proposals ASAP. Something like that, and refer to the contract