saveasteading

Unless it is likely to be very wet there, I'd consider painting in bitumen. Use Blackjack starting with a diluted (water) coat as it will penetrate cracks and crevices. Then a slightly diluted coat over joints and then everywhere, and then a full gunge one. An extra coat over mortar and at the base too. A tar brush is often best.

Old boy surveying enhineer here. Age can help. Grounds how he uses þx terms aurveycand engineer (overused and oftenvabused, I say protectively.) All the advice above is very good. You really do need expert advice, and what you have so far seems sensible. You may be able to dig new foundation inside the garage slab. Breaker and some very hard work with a spade but a good labourer can dig 1m3/ hour.... if you can find one that accepts hard work. Thar way the wet end if the beam will become redundant. Big IF. I'm assuming the beams are not supporting the structure above. The wetness is another matter and there are cellar solutions.

Thanks for this. I'm not convinced on this argument but as i don't know much about these screeds I need to do homework. It does not have fibre. I've gone off fibre anyway as it clumps and is very inconsistent. It is a gypsum product, pumped. 49% club... I don't understand. Brilliant info: I was going to look into this principle. Cracks will be about 0.1mm and will refill with dust. Even if they did somehow open or close again, it would need a minuscule movement in the adhesive... and the grout should give way first. Quite right. In such cases I would often explain the perceived risk with the client, and often they took the saving. It could still be awkward if there was a problem, whatever the contract says. But it's for ourselves using the pension I've saved by making such decisions for decades. i. e. Questioning almost everything, especially the standard ways of doing things that nobody can justify. These are usually "trade" things where they say its best but hsve nil justifiication. Most radical experijents have been on ourselves. Some haven't been ideal but no dramas and usually it's fine. Strangely I see that the ufh pipes are mostly visible by having 1mm or so ridge over them. I'm thinking this has been by displacement of the screed after partial setting, and being walked on. But cracking is only visible in one place I've noticed, though if it's like concrete, there will be millions of tiny cracks/crazing. They didn't put crack inducers at doors and there are no cracks there, which suggests shrinkage is miniscule. I will research further.

That's a " day joint". Not a bad idea though to put a factory edge to work to. As compared to a piece of 4x2.

That's another thing that some trades-people "just do". Screed and slabs indoors do not expand. They may benefit from contraction joints/crack inducers but that is for tidy cracks as opposed to random ones.

If you could expand the logic, or instinct, please? At nil screed of course it would be impossible to tile: at 100mm you appear to agree with my logic. I have some hunch that there is a purpose for membrane at 40 /50mm but I can't grab the logic out of my head. Btw we will have 200m2 of tile (the rest timber laminate) so, at say £10/m2 plus any labour implications, it is a big cost. We're doing well on tile costs so to then add back 1/3 "for peace of mind" wrankles.

We have a lot of floor tiling to do. A recommended tiler says we "really should" have a decoupling membrane. I can't see any evidence that this isn't just an extra earner or " what most people recommend". The stated reasons online are. 1. Peace of mind. For the tiler or me? 2. Waterproof layer. no need. 3. Allows for settlement of the building. It's all on an existing industrial slab, 30 years in use. 4. a) Allows for shrinkage of slab. Ditto b) Allows for expansion and shrinkage and drying of screed. 40mm screed is already cured and isn't going to expand or contract . 5. Allows for thermal movement due to underfloor heating. I don't see that as significant. Any cracks are microscopic. 6. Ideal for Large Format Tiles – Enhances stability and strength. What difference does size make apart from the cost of big tiles? 7. Esp important with ufh due to heating and cooling cycles. I don't see 30 degrees as extreme 8. Enhances strength. I'd think the opposite is the case. To snap a tile it is bridged over soft material and point loaded. A tile cutter doesn't work with the tile flat on a solid base. So if i drop a pot I want the tile to stay solid, not deflect. My other cons. A. £7/M2 or more, plus waste, plus labour. B. We end up with a 10 To 20mm skin of ceramic, barely stuck down or restrained. C. The decoupler works both ways, and could encourage vertical movement under loads, eg table legs, and the grand piano. D. Even if the slab was poor quality, what is that membrane actually doing? Allowing the slab to move but leaving the tiles exactly where they are? I can't see it. E. The membrane acts as insulation on the wrong side. I've looked hard for any evidence and all I can find is that it is normal. Perhaps in a new build of questionable quality it is wise, and for small areas the cost seems relatively minor. I've currently got an old house with poor quality concrete floors. Large expanses of tile have lasted 15 years so far. Lucky again? And a holiday home abroad with lots of tiles on concrete. The only cracks are where I've dropped a log. I should explain. The project in question has 175 reinforced slab on dpm on stone, 30 years industrial use. Then 300mm eps and pir, and dpm. Then 40 to 50 poured screed with ufh. But I wouldn't be asking if I would not welcome opposing views or evidence. Any comments?

Worth insulating then to some extent. Bubblewrap to the structure and pipe insulation.

TLC for me too, unless I need hands-or -eyes-on. The prices are best of near to best. And heavy cable is by the m and saves waste. I think that SF and TS charge as much as they can, relying on just in time purchases on the way to the job. If it's not in stock that is a big failure in my opinion. And the likes of City Electrical charge as much as they can, relying on their trade clients using the credit account for cashflow. My most recent order from TLC was downlighters based on BH advice. Ordered one evening, arrived next morning in their own marked van. That service deserves repeat orders.

I think we are into the times of black plastic. Whatever the material, there will be a standard connector for you to take a loop off. You are going to have to gently dig an exploratory hole at some stage. I suggest now, and the ground may still be soft.

You would need some more certainty before making a formal fuss. But if they have left out the dpm it is a very big deal in competence, and in remedial work. There should be a warranty document which will explain the protocol. At some stage it would involve an independent expert and some testing. Otoh if it was an old house with no dpm, you would paint the surface with a sealant. Bug don't do that... that is a long way down the line. Unless I've mussed it, you having said which part of the country. Just approximately.

Agreed. I had to change a seal in a concealed cistern it is very clever that this is possible through the flush plate.....and it works well again. Part was easy to get and reasonable cost too. The instructions are good too . But my hands are too big/ my clumsiness, and I dropped a small plastic fixing that is then inaccessible, and I had to improvise. I will buy Roca again though.

Absolutely not . You can test this. In a similar area, i.e. same floor construction, but not covered, put a piece of clean polythene down with weight on the edges to hold it down. If there is free moisture then it will condense under the polythene. You could use an upside down glass instead. Putting a vapour barrier on top may be necessary but should not if a) one has been installed under the slab. b) the slab has had time to dry. I've known drain smells to be dish-cloth-like. If the traps are not filled with water, it can come up there.

You both have the right attitude I think. Eventually. Wild flowers and meadows require "not mowing". And it hadn't occurred to me that I could do my " no digging" at any time or place. I may "not dig" tomorrow while watching tv.

It shouldn't be, if the house was weather- tight. The outdoor temperature shouldn't make much difference. Anything else you can tell us? Do the windows steam up? How long did you have the house before laying the flooring? What is the flooring material? Laminated can be several options. Any chance it is simply a smell coming off the flooring material itself?