Smoothing/levelling over a 1960's bitumen sub floor.

[muthafunky]

Hi all.

I've seen many posts about sub floor prep over bitumen residue used to stick down tiles etc, but I've not managed to find many that relate to my situation of having a ~20mm thick bitumen screed sub floor.

What would be my best bet to smooth/level the sub floor out before laying lvt or laminate style flooring. It was previously carpeted.

I've read solutions such as Arditex NA or SBR primer and water based compound or an SBR slurry then compound etc.

What do you think would be my best course of action?

TIA

 

[Wayners]

Has that been put down as a dpm?

 

[muthafunky]

I'm not sure. The house was built in the 60's. There are a couple of chunks missing around the perimeter from where the skirting was and it seems as though there's a plastic sheet of some kind underneath it.

 

[Wayners]

Mine was built 1964 and there is a clear plastic sheet under the concrete base as a dpc.
Then asbestos flooring tiles which was the normal, which I took up and floor looked like yours although the bitumen was very thin.
I scratched up through to the concrete and washed over.
Use 2 pack self levelling compound over so no water used.
Been fine for over 20 years.

Yours isn't like that?

 

[muthafunky]

Unfortunately not. It is definitely a bitumen screen. My mum moved into the house when it was first built and this is how the floor was when they moved it. They had to put their own flooring down.

 

[opps]

Off the top of my head, @dazlight might be able to advise you.

 

[stevie888]

That's mastic asphalt which is a good solid material (used for footway surfacing amongst other things).

I would have thoiught any self leveller that is compatible with bitumen will do, but how bad is the floor? This is a material that can be laid to a very true surface: is it just the dimples you're worrying about? I'd happily lay laminate over them

 

[muthafunky]

That's mastic asphalt which is a good solid material (used for footway surfacing amongst other things).

I would have thoiught any self leveller that is compatible with bitumen will do, but how bad is the floor? This is a material that can be laid to a very true surface: is it just the dimples you're worrying about? I'd happily lay laminate over them

I came across a post about mastic asphalt last night and I think you're right. Unfortunately there are parts of the floor that are 5-10mm out. I was surprised when I checked it as to the naked eye it does look quite flat but there are quite a few undulations throughout it.

 

[dazlight]

That looks like asphalt to me which is good.
Need to get it clean 1st. Best use de greasing crystals from Screwfix.
Then fit in holes with ardex na / fball 1200 pro / Bostik c955 advanced /
Then a liquid Dpm over them sections and any cracks

 

[muthafunky]

That looks like asphalt to me which is good.
Need to get it clean 1st. Best use de greasing crystals from Screwfix.
Then fit in holes with ardex na / fball 1200 pro / Bostik c955 advanced /
Then a liquid Dpm over them sections and any cracks

Thanks daz. After the liquid dpm would you use the smoothing compound again? I've seen mentioned an Arditex NA sandwich, when I've been researching but it's all new to me.