A new problem arises every day with this new build, which I’m cursing and wish we’d never started. The workshop floor is an anhydrite screed with wet UFH. Is there ANY paint suitable for this or must it be tiles? Or can it be a hard vinyl? A hard vinyl needs to be protected with a resin finish to protect it, doesn’t it?

Anhydrite screed is gypsum based and very soft so I wouldn’t go just trying to paint it. Tiles or LVT, or maybe a resin finish on top, would also stand the test of time.

I’d not put anything over it… definitely nothing waterproof
If you were determined I guess you could encase it in resin but surely its easier to just replace it.

Anhydrite screed is fine, once the damn thing is fully dry. That might take weeks or months.

While yours is a workshop, ours is our dining room floor – the moisture readings just weren’t going down. Eventually after speaking to a specialist, we agreed that it Lux have been dry – was the summer of 2018 and the room was hitting over 30 degrees! – so we went ahead and had the LVT laid.

I it is softer than concrete, so I wouldn’t paint it. But then I wouldn’t paint a concrete workshop floor either. Let it fully dry and then tile it properly. You’ll get a decent, hard wearing floor and the benefit of the UFH.

We used it and the plus side is very quick to lay (three days to set) and works perfectly with wet UF heating. Bad news is that tile adhesive is stronger than the screed and some of our tiles have lifted. The tiler initially said he wouldn’t tile it (despite being perfectly smooth and level) because of historic customer complaints. We convinced him to and despite numerous coats of sealant, sure enough some of the tiles have lifted. Where i have tried to repair and lifted the tiles (big 600 x 600mm) lumps of screed have come up stuck to the back of the tiles. The areas where this has been worse are where we have had an undiscovered leaking stop cock and the water main (rubbish plumber) and i think the water has softened the screen. Some of the the perimeter tiles have also come lose which I think is the UF heating causing expansion which has caused the screed to crack.

In short when we do it again i think we will go Karndean!

Surely this is a question for your architect?

Anhydrite screed is fine, once the damn thing is fully dry. That might take weeks or months.

So long as it stays dry…. (or at least stays the same moisture content).
Hence I’d avoid putting anything over it prevents the moisture from underneath escaping…

Anhydrite screed is fine, once the damn thing is fully dry. That might take weeks or months.

Allow 1 day per mm thickness up to 40mm. 2 days per mm for every mm thickness over 40mm.

They don’t really dry any quicker than a sand – cement screed. They’re just easier to work.

We’re goosed then. The tiles and the laminate went straight onto the screed within a couple of months of it being laid, the builder just hand-sanded the screed before tiling. After that the UFH was run at a very low temperature for a month.

This project is lurching into the incident pit with alarming speed.

What’s the easiest get out from a project you have grown to hate? Will anybody buy a derelict house with multiple major problems? Insurance won’t cover if you have multiple expensive repair bills.

We’re goosed then.

You’re not.

I’ve lost count of the number of panicked clients who don’t really understand the build process and who see everything as a disaster.
Just let the builders do their job and try your best to chill out and don’t interfere too much. Unless you have very deep pockets, don’t change things halfway through the build.

Unless you’re project managing it yourself, you’re paying for a finished product. Let the builder stress about the intermediate hassles, that’s what he gets paid for.

The tiles and the laminate went straight onto the screed within a couple of months of it being laid

If the floor finish is already laid, why do you want to change it now?

As long as the reading from their hygrometer (they did test it?) says it’s dried out properly then as long as they sanded and prepped it properly before putting finished flooring down, it’ll be fine.

Most people don’t sand the latence off properly or seal it, a lot of tilers don’t even use decoupling membrane on it with UFH, this is usually the normal culprit for failure, along with putting the UFH on too soon, should wait at least 2 weeks.

Good advice above, but one other point is that you must not use a cementitious adhesive over an anhydrite screed. There are plenty of anhydrite-specific adhesives available.

God reading the advice above taker me back..!

For the OP my experience was one of a paranoid floorer who didn’t want the Amtico he was about to lay to lift (which is fair enough!) but actually discovering that hygrometers aren’t that reliable for determining the moisture content (was a long conversation and I don’t remember all of the detail).

But the detail the guys above are sharing about using the right products is key. To be honest it was the only thing that stressed me out about the work to our house (not even having to pile the foundations for the single storey extension).

What the experience taught me was that, whatever one reads or watches about doing work to buildings, there is no substitute for having done it before (preferably many times). That’s where tradespeople come in – because they have..!

If you only knew half of the shoot we are in with this life change you wouldn’t believe it. It’s in freefall into the incident pit at the moment.

Nobody addressed the question of the workshop floor covering, it got screeded with the rest of the house and that’s it. So when the builder mumbles “we didn’t know what was going on the floor” he is absolutely right and can’t be expected to deliver an appropriate floor.

Are you managing the build yourself?

Did you do the design and specification yourself ?

If the answer to either or both of these questions is no then punt the problem to whichever person you’re paying to do it on your behalf, stick the kettle on and put it out of your mind.

If the answer is yes then decide what it is you actually want and make it happen.

It’s not really a biggie to break out the screed and redo it to get what you need.

I read it that the workshop floor had tiles and laminate already, but I now think you’re saying the rest of the ground floor has tiles or laminate, but the workshop floor has plain anhydrite screed, and you need to find a suitable finish for it?

As I understand it you could use epoxy paint but the surface of the screed would need grinding first. If I was in your position I’d lay 6mm plywood over it, which makes it usable and doesn’t stop it curing. If you don’t like it once you’ve sorted the other problems you can consider a long term solution then.

Do you have an architect on the project? You either had a written specification for the floor covering to the workshop or you didnt, if you didnt you need to ask the architect why not.

If you’re managing the works yourself without an architect you really should have appointed one!

Greybeard is correct, the workshop floor is bare screed. Nothing was ever decided or specified so we can’t blame the architect or the builder. In the rest of the house floor coverings were known from the start so the builder has prepared as appropriate. The workshop has wet UFH so whatever we decide has to work. It’s the builder who has sounded the alarm on this at this late stage.

The workshop is massive, about the size of two double garages. It’s just a small part of the gigantic folly of this ridiculous project. My growing realisation of my stupidity and my remorse is at the base of the mental breakdown I’m suffering. A year ago it was all jolly good fun, meetings with architect, suppliers, let’s have this and can we have that? Ooh a such-and-such would be lovely. Just about the only thing we’ve done right is always pay promptly, ensuring good progress on the build.

Nothing was ever decided or specified so we can’t blame the architect

You can blame him for not specifying a floor finish in the first place and ask him to specify a suitable finish now. That’s his job.

You tell him what your requirements are and he should specify something to meet those requirements.

Unless you’re planning on having heavy machinery or vehicles in the workshop it shouldn’t be a massive problem.

The builder has emailed the architect requesting a solution and so far there’s no reply.

Ecotile interlocking PVC industrial tiles are designed to work with damp subfloors and perfect for garages or workshops (unless you are welding in which case you might have to protect with fire blankets to stop spatter sticking). The underside is ribbed to allow the sub floor to breathe. https://www.ecotileflooring.com/

Our garage is typical 60s build with concrete floor (no membrane under the slab) and bottom two rows of bricks before DPC starts (so floor can get damp). I’ve had them down about 5 years and no disasters where I’ve lifted them / had a look underneath and no mould, damp smells etc (I think I’ve got the thicker 7mm tiles).

They work with underfloor heating – you might just need to leave a bigger expansion gap and be careful to lay at the right temperature as per the instructions.

For that kind of area they aren’t glued down so if you do abandon the house project one day (to return to tropical Lancashire? – sounds like you are having an awful time at the moment) then you can lift and take with you (they aren’t especially cheap). Do not confuse these with the cheap vinyl foamy garage floor tiles. I’ve got smooth slightly textured ones at home (sometimes needs neat muck-off to get them properly clean in the grain). We have the raised dot ones at work but they would be bad for car jacks, trolleys etc.

In relation to your house flooring – Aren’t some laminate / click together LVT advertised as OK for drying out sub floors?

The builder has emailed the architect requesting a solution

In which case, chill out.

There are more components in a house than there are in a car. It’s a complicated process made even more difficult by the fact that pretty much every house is unique.

Imagine if Volkswagen had to build every Passat using slightly different components each time assembled by a completely different team of workers and they had to do it in a muddy field in the rain. It’s one of the few truly bespoke things you can buy these days.

There are always hiccups like this. They always get resolved. It’s just part of the process. The only person losing any sleep over it is you and you shouldn’t be. I promise you it’ll all work out in the end and you’ll look back on it and wonder what all the fuss was about.

Thanks all for the sound advice especially PP above.

Interlocking PVC tiles or looselay vinyl will be fine.

@ globalti – sorry to hear it’s putting you under so much strain.

FWIW our anhydrite screed was the last thing to be finished in the house. We had beautiful Amtico laid in the rest of the ground floor areas as they were the original co Crete floors. Then it just stopped at the dining room door and the open space in there and the kitchen remained without a floor for 6 months after we moved back into the house. The expensive kitchen and other flooring was covered in a fine layer of dust.

But we got through it. Just as PP says. Your workshop will also be finished. You will get there I assure you. And after the stress and expenditure you will come to love it. Promise that.

PS my concrete garage floor is covered in loose lay interlocking pvc tiles (mine are FlexiTile, but they’re all very much the same). They’re fantastic and have solved a problem. Sadly the floor has a bit of a dip in the middle and heavy rain sometimes seeps under the garage door and underneath the tiles. No biggie – I just whip them up, dry the concrete floor and re-lay the tiles. They’re a really excellent solution.

PPS it will all be ok..!!!!

Are loose lay interlocking vinyl or PVC tiles suitable for under-floor heating? Do they have a fluffy underneath for cushioning?

Yes (underfloor heating).

Read the info page on the ecotile link I posted above. Not cushioned so they are good for spreading contact loads under heavy benches etc. They have a ridge pattern underneath so vapour can escape your heated damp floor. 3rd pdf on this page
https://www.ecotileflooring.com/support/installation/

If you are standing in one place for a long time just get a rubber anti-fatigue mat (just like they do in Machine shops etc).

Our new build should hopefully be done in 7-8 months…. I’m takingy garage floor with me 🙂 (and buying more)

You my friend are a genius. Thank you so much!

Just glad people have managed to find you some brightness in the dark.

From your username I guess you used to live near Craig’s bike shop 🙂

I admire what you are doing and echo it will all be worth it. We almost bought a project house during lockdown 1. I did a good chunk of CAD redesign before we decided it would be a great layout for our lifestyle but not financially viable. The sleepless nights / buzzing mind from that initial design process also made us realise all the build details would probably break me….

Hence now on a good enough but not perfect new build where a small developer can have all the stress.

Yes I used to go to Ride On a lot. I bought my hooligan bike from there too.

I so wish we had taken more care at the design stage. We have ended up building a house that’s too big and too expensive, which is causing me a lot of stress. In fact I wish we had seen the coming pandemic and stayed in Lancs.

I so wish we had taken more care at the design stage. We have ended up building a house that’s too big and too expensive, which is causing me a lot of stress. In fact I wish we had seen the coming pandemic and stayed in Lancs.

I wish it was being filmed for Grand Designs…..only joking

At least you aren’t that bloke with the incomplete house just outside Croyde, screwed by his architects ambition

It’s probably worth doing an exercise on what else hasn’t been specified yet, then get decisions made, there’s plenty of people willing to give suggestions on here for odd ball issues

I wish you all the best on your build. I am in the middle of a self build and hitting a few problems myself, Very stressful times but I’m sure you will soon see light and the end of the tunnel.
Hope you can update on your progress and how you overcome the screed issue.

I think I am that bloke, screwed by his own failure to speak up when harbouring doubts and by allowing himself to be cajoled and browbeaten into spending a frightening amount of cash on a project he’s deeply unhappy about. If you knew the amounts involved and the size of the project in the most inappropriate location you would go pale with shock.

Don’t forget how grey, wet, cold and miserable East Lancs can be. You moved away for a reason.

If you go with the 7mm Ecotile and don’t like it then I’d seriously buy back 18sqm off you (only caveat being that our house actually gets built!).

At least in East Lancs we weren’t 12 miles from the nearest shops and facilities, 28 from the town and we had security, comfort, no debt and cash in the bank. It may have had its downsides but it suited us perfectly.

At least it hasn’t snowed yet.

You’ll start to feel better when you start to see progress, what’s your estimated current move in date?

Builder still hopes mid December