Laying wood floor over concrete that previously had tiles

[AlanAudio]

I'm about to lay a bamboo strip floor onto a concrete surface. The suppliers recommended that I glue it down and so I've ordered all the stuff to do that.

Having lifted the carpet, I've discovered that the little bit of floor I previously examined is good bare concrete, but much of the floor shows signs of once having had plastic tiles with patches of what seems to be old adhesive. It's medium grey and almost as hard as the concrete. The thickness is pretty minimal, less than 1mm and it's stuck on very well.

Following advice found here, I was intending to use a water based floor levelling compound before laying the floor. What should I do about the patches of old adhesive ?

Can I use levelling compound over it, or does the adhesive have to be removed first ?

If it has to be removed, how do I do that ?

The skirting has been removed and there are small gaps between the floor and the walls. What it the smart way to stop the levelling compound running into those gaps ?

 

[AlanAudio]

The residue from the adhesive tiles that I previously mentioned is slowly being removed with the help of a heat gun. In the absence of any advice saying it would be OK, I felt it was safer to be rid of it.

That leaves my query about containing the floor levelling compound. What's the approved way to stop it running off into the gaps at the bottom of the walls ?

 

[flooringman]

You are right to remove any old adhesive before putting down a screed. I have a machine that I use for this otherwise it can be a pain - as you have no doubt found out?

If you are gluing down the new floor you do need to check for moisture in the sub floor.

You can get strips of foam to contain any screed but unless there are any deep holes around the perimeter I wouldn't bother. If I need to stop the screed from going from one room to another I use a strip of carpet gripper or similar - just stick it down with some double sided tape.

 

[mac391]

Use decorators caulk for the gaps behind the skirtings, but read on first!!

You should test you sub-floor for moisture but as far as know you can't hire the correct instrument (hygrometer) for doing this. it's realy important !! Maybe you could find a floor layer to do this for you, it's a 48hr test that i would charge @ £100 for. If the floor moisture content is above 75% RH then you need a DPM.

Or !! you could put a liquid DPM down without testing, to protect your floor from moisture. Realy though, your supplier should have given you this info.

One other alternative is, read the instructions to find out if your bamboo is suitable as a "floating" installation and proceed from there.