"floor primer" (?)

[AL_n]

I just bought a tub of self-levelling floor screed to level out a roughly- screeded floor prior to laying self-adhesive tiles. The instructions tell me to first apply "floor primer", diluted 1:3. It tells me to then apply the self-levelling mix when the floor primer is still tacky. Does anyone know what type of floor primer is suitable? Will diluted PVA do? The floor has no rising damp issues.

Thanks,

Al

[The Natural Philosopher]

diluted pva is fine, Dilute with water, not brandy. Hic!

[Tim Watts]

What was the make of the self levelling compound?

F Ball products usually stipulate P131 which is a neoprene primer that both seals and provides a highly tacky surface.

In the absence of any specific instructions, a diluted (about 1:2) SBR to water will probably do. It will seal, be damp resistant and provide a moderate tack surface that is very compatible with cement based products.

PVA might do, but it doe not penetrate well and any damp will soften it. And

20 odd quid for 5 litres (more than enough) is not worth arguing about.

[AL_n]

The Natural Philosopher wrote in news:kbkjtq$vlm$1 @news.albasani.net:

Thanks.. That's what I initially hoped too. However, I just read online that another self-levelling floor screeed ('Level A' sold by Screwfix) prescribes the use of an epoxy primer.

The stuff I bought from B&Q has the brand name "Diall". It calls itself "Level a floor screed system" (with a small 'a'), so I'm wondering if it's the same stuff that Screwfix sells, but under a different brand name. The stuff I bought is a 2-pack product (powder, plus liquid). I wondered if that suggests it is resin-based (epoxy or polyester). I'd take a whiff of the liquid, to get a clue, but if I break the seal on the tub, I won;t be able to take it back. (I will want to take it back if I find out I have to use an expensive primer - and I assume any epoxy primer is going to cost a lot more than the £10 I paid for the self-levelling screed!)

Al

[AL_n]

Tim Watts wrote in news: [e-mail]:

Thanks... The brand is "Diall" (from B&Q). It describes itself as "level a floor sceed system (self-levelling)".

There is a fast-setting self-levelling screed called "Level A" sold by Screwfix that stipulates the use of an epoxy primer. I'm wondering if it's the same stuff but with a different brand name.

Does anyne know what the term "Level A" and/or "Level a" indicates? It's a term I've never encountered before. Is it simply a meaningless product name, or does it indicate what the stuff is made of?

Al

[AL_n]

"AL_n" wrote in news:XnsA137B36AFCBB1zzzzzz@130.133.4.11:

Could you please clarify what SBR is?

I've just found reference to an acrylic primer describing itself as 'suitable for use prior to applying self-levelling compounds'. I already have a tin of acrylic paint. I'm wondering if I should just dilute that and use it (rather than PVA). If I remember correctly, the resin used in acrylic paint is marginally superior in some way to the version used in PVA paint.

Al

[harry]

You need to find out what is recommended by the screed manufacturer. They will have it wherever you got the screed from.

[Tim Watts]

Hmm

Never heard of either of those.

But the Screwfix piccy shows it is branded:

"Stikatak" which belongs to

quoted use of "epoxy primer" seems a little suspicious. I've used epoxy as a damp proof membrane and the odd thing is that it is actually not at all sticky when dry - so much so that F Ball list some very specific coatings that should be applied before self levelling compound is poured over - in their case, P131 neoprene primer again.

Where does it say to use an "epoxy" primer?

[Tim Watts]

Google would have told you:

I've just found reference to an acrylic primer describing itself as

Despite what some folk think, I am very dubious about PVA for a flooring application. It barely penetrates and is not good if it gets damp (with the possible exception of a waterproof version). SBR once set is 100% capable of withstanding wet and penetrates substrates extemely well.

I cannot answer for your acrylic primer, but for an application where failure will be an utter PITA and it will be subjected to shocks and loads, I would take guidance from the manufacturer and if that was not forthcoming, then default to SBR and nothing else. I've use SBR for all sorts of (legit documented) purposes since being introduced to it from this group a few years back.

The documented uses are:

Sand/cement Screed additive allowing screeding down to 10mm thick;

Preparation for the above (paint dilute mix on floor liberally, then apply a SBR/Water/cement slurry)

Painting on fresh shiny plaster prior to tiling (documemented by BAL for Greenstar tile adhesive)

(Undocumented) pouring literally several gallons over a very friable piss poor screed and dusty concrete subfloor prior to remedial levelling compound and epoxy DPM. The floor is still there with its slate tiles after 3 years so far.

[newshound]

SBR = synthetic butadiene rubber. SBR primer is "PVA with attitude" and as suggested above is likely to be more suitable for this job than PVA.

Plenty of hits if you google for SBR primer.

Personally I would not use acrylic paint as a substitute for PVA, it will contain fillers and pigments and consequently less resin. If your SLC cost a tenner it won't be epoxy based and therefore should not need an epoxy primer IMHO

[AL_n]

Tim Watts wrote in news: [e-mail]:

OK, it seems that SBR is the better choice. Hopefully I can cadge half a pint from someone locally, because that's all I need.

Thanks to all for the input.

BTW, I remember once using some stuff commonly known as 'stabilising solution'. It was a clear liquid intended for spraying onto unsound old plaster and such. I wonder what that consisted of. I'm pretty sure it wasn't PVA.

Al

[AL_n]

newshound wrote in news:50ddfe27$0$31889$c3e8da3 $ [e-mail]:

not need an epoxy primer IMHO.

Good point. Thanks.

Al

[AL_n]

"AL_n" wrote in news:XnsA137E8E06600Dzzzzzz@

130.133.4.11:

PS... It does specify that the said 'floor primer' should be diluted with water at a rate of 3:1. So the primer they recommend is clearly dilutable with water.

Is SBR dilutable with water?

Al

[Tim Watts]

Yes - absolutely.

a very useful reference. Sorry, it refreshed my memory - for sealing purposes you can go down to 1:5 SBR:Water

1:3 is less economical but will form a stronger layer once it has penetrated. A small amount on a test area would be worth doing.

If the aim is to really seal and penetrate the surface, you need to throw everything down at once. After the first coat sets (< 30 mins - 1 hour) you will not get much absorption on a second application.

[stuart noble]

As a long time fan of SBR (I was using it when it was bloody expensive and difficult to find), I would certainly use it where there is any possibility of damp. Where there isn't, both sealer and screed can be pva based IMO. PVA certainly mixes well into mortar, whereas SBR doesn't for some reason. It almost behaves like a solvent based additive

[harry]

I think it's important to put on several coats of PVA, the first ones diluted with water. The subsequent coats suck up less as you apply them until you have a shiny surface. You can then coat with cement made up with PVA and water.

[stuart noble]

IMO the main purpose of a sealer is not to act as a waterproofer in itself but, in the short term, to prevent the water content of the mortar soaking into the masonry before it's had time to cure. This is why it often sets perfectly on the inside of a bucket but falls off the wall :)

[AL_n]

stuart noble wrote in news:5dVDs.1446983 $ [e-mail]:

That's how I understand it too. However, it seems to make sense to use something that isn't likely to be degraded if it gets damp for any reason.

Al