Sealing a new screed.

[headworx]

Another quickie hopefully.....

Just had a new floor and screed in the kitchen I've had built.

The builder and a relative who used to be in the trade advised using a very weak unibond mix to seal and keep the dust down.

I've read before in here many times that trade peeps dont like doing this - Also a friend mentioned that some adhesives (going to tile the floor with 60x30 Porcelain tiles) react in a bad way to PVA based stuff and may not stick properly.

What are your thoughts on this?

Do I weak unibond and hope for the best or is there special sealants I can use (and are they dear?)

I'd have thought the builder knew what he was doing and he knows I'm tiling it, but wanted to double check 1st.

Thanks peeps.

 

[tpt]

its a great way of keeping the dust down if your going to wait for 12 months! but if you already know your tiling it, dont.

before you do tile it will need to completely dry and then just follow the instructions on the bag of the adhesive. a lot depends on the type of screed it is.

 

[headworx]

Cheers TPT,

Its been done a few weeks now - Ive read it can take up to 5 weeks to dry, but I'd say its dry now.

Wont be doing this for a few weeks as I got other things I need to do at the house in the meantime so wanna make sure its dry.

So in your opinion, I dont need to 'seal it' as such? Just get the adhesive and follow whats on the bag?

I wont use ready mix and will be decent stuff like BAL, will prob get the rapis setting stuff too so I can get a fair bit done in small bits.

I'll have to find out what type of screed it is off the builder, it looked like he put it down quite dry which is perhaps why its dried well. Mind you was only 2 inch or so anyhow.

 

[headworx]

Just another thing,

when I mentioned 'sealing it' i meant do I have to prep it before tiling.
Is sealing and priming the same thing?

I just dont want to confuse or mislead people with my lack of terminology, or I might get the wrong advice for whatI intend to do.

 

[tpt]

ah right. yes sealing and priming would mean the same thing in prep - best refer to it as priming. some tiles need sealing so you will see that referred to as well.

both BAL and granfix have a tech support line that are very helpful too.

 

[Richard C]

If by Unibond you mean standard PVA, never use it on a tile base, it’s not a suitable tile primer. A builder won't necessarily have a clue about tiling.

Never use anything other than powder cement adhesive eon floors, tub mix is unsuitable. You should always follow the manufacturer’s instructions regarding priming, BAL I know but you need to determine what type of screed you have. If it’s Anhydrite (gypsum based) you must use an acrylic primer (Prime APD) to avoid reaction between the cement in the adhesive & gypsum in the screed but conventional sand cement screed is usually OK without primer unless overly dusty but if in doubt, use the acrylic primer; follow the instructions in each case.

With largish tiles, the floor needs to be flat & hopefully being as it’s new. Use a large format trowel - 20mm round notches, 13mm deep, at 28mm centres.

 

[headworx]

Oops, sorry for delay...Thanks Richard - You're quickly becoming the one stop shop for answers.

Just like to say your advice on this forum is very helpful - It would be a big loss if you ever left here. Not borwn nosing, just credit where it's due.


Will be doing this over the next couple of weeks now as the kitchen order was placed at Selco yesterday so need to pull my finger out.

Priming Screed
So I'm gonna 'prime' with Acrylic primer just in case (It is a concrete screed by the way).
Any suggestions for a cheap decent brand and where to buy?

Planning layout
I have a 20m2 area and will be laying 60x30 procelain 10mm tiles in brick pattern (1/2 bond I think its called?)

Any advice (above and beyond the sticky advice) on the planning stages of laying anyone? Although the sticky says start in middle, do I want the 'best bit' to be where you look when walking out? Might hae to upload a pic of layout perhaps for advice?

I'll be buying BAL grout and prob the Bal/Weber adhesive.
Someone mentioned the adhesive at Topps is the same stuff as BAL, is that BS or would the cheaper adhesive be ok considering it's on a concrete floor?

Sealing tiles
The tiles dont say they need sealing but a review on the B&Q site says to do it as theirs stained - Any reccomendation on brands of sealer - Also do I seal them first or wait till they are down (before grouting)?

Soz for all the Q's (I'm sure there will be more to come)....

Finally I got a quote for someone to lay them (supposedly a bit cheaper as its a friend of a friend) and for the 20m2 I was quoted £340 labour only.
Is this considered cheap?? (Live in Brum if that has a bearing on things). He said it's usually £20/m2....Just seems a bit pricey to me......Mind you I am skint and tight!