Laying new floor - needs DPM?

dunroving

Doozergirl wrote: »

Any idea what it's like next door?

I've got no idea if there could be retained moisture from the leak. It's not something I've experienced, but comparing it would be helpful, I guess.

I chatted with next door, but their flooring (laminate, I think) was in place when they moved in, so they don't know if their flooring was placed on top of the old Marley tiles.

All the houses around here were built the same, so I plan to knock on a few doors later and ask questions.

Humidity reading is up to 95% this morning. I don't think this is residual misture from the leak, because there wasn't that much water in the living room (luckily, most of the leak went out through the cistern overflow), plus I had two huge fans and two industrial strength dehumidifiers running 24-7 for about 3 weeks.

I plan to try the hygrometer in the kitchen too, as that's where the main leak was.

dunroving

FreeBear wrote: »

The only way to be certain that there is an existing DPM in/under the current concrete floor is to drill a test hole. However, this will puncture the DPM (if there is one) and need to be suitably repaired. Digging out the current floor and putting down a new one, whilst expensive and disruptive, would give you the opportunity to upgrade the insulation..

I used LVT click-loc tiles in my kitchen - Half concrete (with DPM) and half suspended timber - I still put down a large sheet of heavy guage polythene DPC followed by 5mm wood fibre underlay before fitting the tiles. The plastic will prevent any residual moisture tracking up through the flooring (LVT is waterproof anyway), and the bare concrete under the units will allow moisture to evaporate.

It up to you if you follow the recommendations of the loss adjuster. But I would use the self leveling compound, and apply a DPM (a plastic sheet that can be removed at a later date if problems arise) on areas that are to be covered. Leave bare, untreated concrete under any base units.

markin wrote: »

As said its the perfect time to upgrade the insulation at least in the living room, or to go with wet underfloor heating.

Not sure how insulation is linked to the floor - under-floor insulation? (not something I'm familar with).

Regarding plastic sheet DPM, I'm probably going with glue-down Karndean Van Gogh or Polyfloor Camaro (also glue-down) - I'm guessing a plastic sheet DPM wouldn't work in that case. (?)

markin

Its a common complaint that old solid concrete floors are cold, Have you lived in this house over winter yet?

FreeBear

dunroving wrote: »

Not sure how insulation is linked to the floor - under-floor insulation? (not something I'm familar with).

Regarding plastic sheet DPM, I'm probably going with glue-down Karndean Van Gogh or Polyfloor Camaro (also glue-down) - I'm guessing a plastic sheet DPM wouldn't work in that case. (?)

If you were to remove the concrete floor, current building practice is to put some 100mm or more of Celotex/Kingspan type insulation down before pouring the final screed layer. This is to comply with current building regulations regarding insulation of properties.

As for a DPM - The new vinyl tiles will provide a more than adequate barrier to moisture. Just follow the manufacturers instructions for surface preparation, and you shouldn't have any problems.

markin wrote: »

Its a common complaint that old solid concrete floors are cold, Have you lived in this house over winter yet?

Certainly noticed the cold on the concrete half of my kitchen floor. The 5mm of wood fibre underlay made a huge difference to the feel under foot.

Doozergirl

FreeBear wrote: »

As for a DPM - The new vinyl tiles will provide a more than adequate barrier to moisture. Just follow the manufacturers instructions for surface preparation, and you shouldn't have any problems.

With that much moisture, they'll insist on putting down a liquid DPM before laying, or they won't provide a guarantee with it.

If everything else around the house is dry, I'd not really have a problem with laying it.

But what is around the house? Got a good 150mm of clearance below the DPC?

dunroving

markin wrote: »

Its a common complaint that old solid concrete floors are cold, Have you lived in this house over winter yet?

I lived in it over the winter, but at the time, it had carpet over the old Marley tiles, over the concrete. I certainly never had an issue with cold floors then. One of the reasons I am going with luxury vinyl, though, is warmth underfoot.

dunroving

FreeBear wrote: »

If you were to remove the concrete floor, current building practice is to put some 100mm or more of Celotex/Kingspan type insulation down before pouring the final screed layer. This is to comply with current building regulations regarding insulation of properties.

As for a DPM - The new vinyl tiles will provide a more than adequate barrier to moisture. Just follow the manufacturers instructions for surface preparation, and you shouldn't have any problems.

Certainly noticed the cold on the concrete half of my kitchen floor. The 5mm of wood fibre underlay made a huge difference to the feel under foot.

Ah, thanks for the explanation. My thread title may be a bit misleading - the concrete won't be removed, there will be a layer of self-levelling compound (and by the looks of it, this will be followed by a DPM).

Interestingly, I called on a neighbour earlier today who bought his house last summer and has had major renovations (full-width two-storey extension to the back, and the whole room layout up and down changed).

The whole of his first floor is floored in ceramic tile, which looked really good. I got chatting about the old Marley tiles, and it turned out he/they ripped out all the tiles themselves, and assumed there was a DPM below the concrete. He seemed a bit concerned when I told him what readings I was getting, but he has some sort of thermal layer under his ceramic tiles, which also may help to form a barrier to moisture. He's also installed underfloor heating, which presumably will help to prevent moisture(?)

Bottom line is that I think most of the neighbourhood has at some time ripped up these tiles, and not had subsequent issues (but see my post below).

dunroving

Doozergirl wrote: »

With that much moisture, they'll insist on putting down a liquid DPM before laying, or they won't provide a guarantee with it.

If everything else around the house is dry, I'd not really have a problem with laying it.

But what is around the house? Got a good 150mm of clearance below the DPC?

Spot on. The floorer said if the moisture readings were > 75% he would put in a DPM.

From outside, I see about 2 courses of dark brown bricks above ground/soil level, before the DPC (which looks like slate). Then the caramel-coloured bricks the house is made of starts. Although the soil around here is very heavy clay, I don't generally get any pooling of water against the sides of the house.

The surface of the concrete floor is just about level with the DPC in the external walls. I'm trying to get an idea whether that is good or bad! (First house I have ever owned that had a solid floor; I can get my head around a DPC with suspended floors, but this is a bit more confuzzling).

[I may get in touch during next week about what I'm planning for the house, and ball-park budget. Then you can tell me if I'm dreaming. ]

dunroving

Argh, another update. The hygrometer has been used in several places on the ground floor, and where the water leak had affected, the readings were all above 95% RH. In the other areas, they were in the 70s.

I've called Saga, who my policy is with (thought it was time to start naming names, as this is an MSE forum, and I want to at least give MSE-ers some helpful information). They underwrite the buildings part of my policy to Acromas, who in turn have contracted Davies Group as the loss adjusters. Davies have in turn subcontracted to various companies - Midland Response (cleared out the rubble from the leak, including the kitchen ceiling, took moisture readings, installed dehumidifiers and fans for about a month)), Aspect Contracts (removed the asbestos-containing Marley floor tiles), and Blyth Group (who were subcontracted to do the restitution/building work).

Long story short, Midlands Response took the post-dehumidifier readings using a handheld moisture reader, *before* Aspect Contracts removed the Marley tiles. The readings I have from the floor hygrometer indicate there is a lot of residual dampness still in the screed - it probably has nowhere to go, if as suspected there is a DPM underneath it.

>>sigh>> So Saga Customer Services are calling Acromas, so they can instruct Davies to instruct Midlands Response to bring the dehumidifiers back.

I've never made an insurance claim of any sort in my 62 years and hadn't realise how convoluted the claims and restitution process is in these situations.

Doozergirl

Sounds like a nightmare.

There's 'only' three companies involved in fixing my car after an accident and it's not totally fixed after three months!

They don't make it easy for themselves.

Fingers crossed the dehumidifiers do their job!

How long were they in for the first time?