Fixing Plywood to Concrete Floor

[blade runner]

I'm planning to have an Amtico floor fitted in my hall. There is quite a bit of floor depth to make up to match the FFL in other rooms off the hall, so the flooring company that came round to quote advised that I would be best to ply over the existing concrete screed. A latex levelling screed would have worked, but the hall used to have a parquet floor and so has a nasty black adhesive remaining which is just about impossible to get off and problematic to get a latex to bond to (apparently).

Anyone advise what the best way to fix the ply sheets (15mm) to the screed would be? Do they go straight down onto the screed or should I also use some form of thin-set adhesive underneath before mechanically fixing? The flooring guy suggested normal rawl plugs and screws to fix the sheets but I was wondering if concrete screws or express nails would be easier and quicker to use?

Any advice appreciated.

Cheers

[m4ckg]

plug and screw it every 12" minimum and if you want put some Gripfill on aswell.

[Simpo Two]

Watch out for central heating pipes!

[bga]

blade runner said:

A latex levelling screed would have worked, but the hall used to have a parquet floor and so has a nasty black adhesive remaining which is just about impossible to get off and problematic to get a latex to bond to (apparently).

This is the stuff you want: http://www.ardex.co.uk/arditex_na.asp

We used it to provide a good base for tiling over bitumen adhesive left over after we lifted a load of parquet. Being paranoid I called Ardex & one of their tech guys confirmed that it was designed for just this kind of thing.

[Tacagni]

You could plywood the sub-floor but you would be better off putting a latex skim down. If its quite deep you could put chippings (washed) in but then you would have to apply a second coat.

[blade runner]

Thanks for all the responses.

Flooring company have said that they can use the Arditex NA on top of the existing screed, but costs to build up the floor with latex products is around £750 compared to a little over £150 if I just buy and fit 15mm ply sheets myself. Assuming I make a good job of fitting the ply, is there any reason the finished sub floor will be significantly inferior to a latex screed?

I'd like to get the best finish possible, but £600 is quite a saving...

[dave_s13]

Amtico have specific info on subfloor prep if you have a dig through their site. Marine grade Plywood is bloody expensive btw....is that what you priced it on?

http://www.amtico.com/uploadedFiles/Resources/UK/I...

What is Amtico anyway? Wood, egineered, tiles....????

Me and a mate put down 45sqm of 18mm T&G oak over the weekend - hard bloody work



That was laid directly onto a combination of floorboards, chipboard and screed (bitumen paper as underlay on the wooden bits). It was glued to the screed bit. Laying onto the wooden substrate was a peice of pee with a portanailer as it wacks everything tight together. The glued bits were not so easy!

It looks bloody lovely and was incredibly cheap really. It's how long it stays that way that you pay for though...time will tell.

Edited by dave_s13 on Monday 14th February 21:38

[seeby]

Blade Runner, The way to go is,F-Ball 131 Primer onto your old parquet adhesive (cheap as chips ) This will bond to the adhesive and give a good key to lay F-Ball Stopgap 300 self leveller. It,s a water based screed and goes bl**dy hard. Ithink this would give a better feeling underfoot than plywood,as you tend to get a tappy noise on ply unless you really stick and screw it well.Good Luck