Self Levelling Screed

I'd appreciate advice.

I'm refurbishing my conservatory. The floor is concrete but is not universally flat because of an inexpertly filled in channel for pipes, wiring etc. I'd like to lay either carpet tile or textured vinyl tiles. Does anyone here have experience on the successfulness (or otherwise) of self leveling screeds?

TIA JonH

Reply to
JonH
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Used as directed, they are very effective, although the "self levelling" claim is slightly misleading.

If they were fluid enough to be truly self levelling, the high water content would mean that they wouldn't be very strong when they set, so they are only to some extent self levelling. A little work with a steel float does the trick. Gently does it!

But with that proviso, they are very good indeed, and ideal for your purpose. Depending on how uneven the floor is, you may need to apply a second layer. The ones I have used have all had a maximum thickness of 5 or 6 mm. Thicker than this, and you need two layers.

Reply to
Bruce

I've used SL for several floors where I either tiled or laid laminate. I have not tried it with carpet, but can't see why it wouldn't work.

Despite it's name it is not SELF levelling. You have to float it to a rough level and then it self-smooths. Easier to do than describe though. On old concrete a brushed-on coat of SBR is a good idea, and then screen when the SBR gets tacky.

R.

Reply to
TheOldFellow

Tim will be along in a moment I'm sure - he has done tons of screeding recently IIRC.

F Ball Ltd seems to be the business, although I have used the Wickes Master stuff (which think is made by them). Do check the sell by dates on the Wickes stuff though, I've had a bad experience with an out of date batch.

As Bruce says, it needs a little work with a float and works in thin layers, but its easy enough to do.

Reply to
The Medway Handyman

The Medway Handyman wibbled on Sunday 28 February 2010 16:35

Yes. I have heard what Bruce says to be true of some of the gunk sold.

If the floor is dry (ie there is a functioning DPM in there) then the one true answer by my own experience is:

F Ball Stopgap 300 HD. You would need P131 (probably) to prime the existing floor. Try to do a single pour to get at least 3-5mm (5mm flows better than

3mm, but I have done a 21m2 floor to 3mm to within +/- 1mm or so in a single pour with help).

You can buy it from here:

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you *must* have this:

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the smaller version).

Removing air bubbles sounds fancy, but the other effect is it helps the mobility of the fluid to achieve self levelling.

The approach I used (from this forum) was:

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not a clear picture. It's a T bar of 2x1" wood with 3 round head screws set 3mm out from the edge of the bar. This allows you to push the material around to about the right level quickly and from a standing position.

You also need a big bucket and a power mixer (drill type OK for 2 bags, plasters mixer will do 3 bag mix). Mix in the middle of the pour area if pouring a lot.

HTH

Tim

Reply to
Tim Watts

Tim:

Thank You!!!!

I can handle that.

Regards JonH

Reply to
JonH

Tim Watts wibbled on Sunday 28 February 2010 17:33

Oh, and make it up with the max water according to the datasheet, not the medium or min.

Sorry for being terse, have flu.

Reply to
Tim Watts

snipped-for-privacy@Underthewagon.net wibbled on Sunday 28 February 2010 17:41

How big is the floor?

Recommend you thoroughly read the datasheets on F Ball's website too :)

Reply to
Tim Watts

Not very succesful IME.

If I wanted to do it again I would lay down battens a few mm up and level the top of those, and fill the boxes scraping off the top to get it all level.

relying on its alleged natural propensity to level didn't work for me.

Reply to
The Natural Philosopher

3m x 4m. Access is from both ends of the 3m side.

Reply to
JonH

Surely you mean 'man flu'?

Much worse than normal flu. Have a large whisky.

Reply to
The Medway Handyman

Don't apologise, Tim, your advice was excellent. I will happily defer to it as you have had more recent experience of screeding large areas. The DIY sheds' self levelling screeds are still useful for smaller areas, even if they don't do exactly what it says on the tin.

Anyway, thanks for your detailed advice, which I have filed for future reference.

Reply to
Bruce

That's what I thought. B-) You know you have 'flu and you are in bed and some one tells you there is =A350 note in the kitchen and you can have it if you can get to it and pick it up in the next hour. If you succeed, you haven't got proper 'flu.

Reply to
Dave Liquorice

The Medway Handyman wibbled on Sunday 28 February 2010 20:49

Hehe.

No, real flu AFAICT. Only had it once before ( and maybe as a kid). Not as bad as last time, but overdosing on lemsip just to stop shivering and it's been going on for over a week.

Can't sleep now, lemsip fixed everything except sinus aches which are just annoying.

Reply to
Tim Watts

snipped-for-privacy@Underthewagon.net wibbled on Sunday 28 February 2010 20:04

12m2 - so that could be done with a 3 bag or 4 bag mix.

Of course, you have to make some allowance for the low bits - you need 3mm thickness minimum (unless you are going to try to feather it in - which isn't as good, except for small areas IMO).

Take a survey with a long straight edge and see if you can roughly reckon how much volume is needed to fill the hollows. On top of this, you have to apply a further 3+mm over all to get the self levelling effect. I suspect 4 bags will do it for you unless your hollows are vast. Best done IME with 2 x

30-ish l (or bigger) buckets - 2 bags each.

If the water is measured in both, both bags are slit and open and sitting next to the buckets and you have a friend who can pour whilst you mix with the drill mixer (mixing should be done as the power goes in) you'll have enough time.

Allow 5 mins MAX to mix each bucket (have a clock) - have everything ready, including hose outside and wellies on.

You will have primed the floor with green P131 the day before or at least in the morning.

Once you've mixed both buckets, kick them over, drain thoroughly and throw outside.

It's against the clock now, but with mental preparation, 4x3m will be very easy.

Allow 5m max to use the t-bar or float to push the stuff around. You are now T+15 and have 10-15 mins left.

Use the spiked roller to work the mix - this will disperse the air and help it to retain fluidity. Work for 5-10 minutes. The surface reflects like a pond, so looking at reflections of window frames etc can help you gauge if it's settled out right.

Walk towards the door and roller your footprints out as you go.

Hose everything immediately (ideally your helper will have hosed the buckets).

Wait 60 minutes - test, but it should be hard enough to walk on - but go gently, best not to abuse it for another day. After that it's pretty much like iron.

Sometimes, if there is a lump in the underlying floor, you can get a lump in the top as it clings over the lump. That's why the surveying is a good idea

- if you can get 3mm or more over everything it should go well.

Do not under any circumstances fail to use the P131 - this helps adhesion, but it also prevents water being sucked out of teh Stopgap 300, which is where a lot of the other products fail.

Reply to
Tim Watts

It really doesn't have a natural propensity to 'level' at the correct dilution. It has a natural propensity to 'flatten'. You level it first with a float. It should be called 'Self Flattening Screed' IMHO.

R.

Reply to
TheOldFellow

Not a very large area, but you still have to be well organised and think the thing through. Also, there is a big difference between the 2 pack latex screed and the one pack, the latter being more forgiving IME

Reply to
stuart noble

That does sound more like 'flu but into the recovery phase now. Could you have succeeded in the =A350 test a week ago?

Hope the sinus trouble improves, that pain is on par with ear and/or tooth ache. Have you tried making like a bat? Lie face down on a bed then hang off the edge so you head is upside down, it'll be bloody agony to start with but may well drain things out so have some tissues/kitchen roll handy. The relief is worth the pain...

Reply to
Dave Liquorice

Dave Liquorice wibbled on Monday 01 March 2010 10:07

What's the £50 test?

Ah, proper DIY advice. I'll try that :) It's really weird lying in a dark room meditating on yer sinuses as the aches come and go...

Reply to
Tim Watts

As posted last night. You are in bed "ill". Some one tells you there is a =A350 note in the kitchen and you can have it if you can get to it and pick it up in the next hour. If you succeed, you haven't got 'flu.

Reply to
Dave Liquorice

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