600mm x 400mm Slate floor on bitumen

[cametcalf]

Hi there,

I'm looking to tile the whole downstairs of my house with a machined 600x400 slate floor tile the sub-floor is bitumen and I wanted to know what surface preparation and adhesive to use?

Any advice greatly received.

Thanks,

 

[Wayne_Phipps]

Hi there,

I'm looking to tile the whole downstairs of my house with a machined 600x400 slate floor tile the sub-floor is bitumen and I wanted to know what surface preparation and adhesive to use?

Any advice greatly received.

Thanks,

Hi,

Is the bitumen an adhesive residue left behind after removing vinyl tiles such as marley etc, or is it a flooring grade asphalt? Flooring grade asphalt can be tiled with basic prep work.

Although there are levelling compounds available that are specified as suitable for laying over bitumen residues prior to tiling, it would be much better practice to try and mechanically remove as much of the bitumen as possible to avoid the potential failures associated with it, prior to using one of the levellers.

What tends to occur is that as the cement based adhesive cures over time and increasing its bond strength, it pulls of the bitumen layer which is weaker than that bond. To this end remove as much as possible, so there is more contact with the substrate underneath the bitumen. With tiles of that size/type you will most like have to use a thicker bed of adhesive, so make sure it is a low shrinkage product or suitable for the thicknesses required as the standard cement based adhesives tend to shrink and pull bitumen off easier.

This is all based on the floor being a solid screed/concrete etc.

 

[cametcalf]

Hi,

Is the bitumen an adhesive residue left behind after removing vinyl tiles such as marley etc, or is it a flooring grade asphalt? Flooring grade asphalt can be tiled with basic prep work.

Although there are levelling compounds available that are specified as suitable for laying over bitumen residues prior to tiling, it would be much better practice to try and mechanically remove as much of the bitumen as possible to avoid the potential failures associated with it, prior to using one of the levellers.

What tends to occur is that as the cement based adhesive cures over time and increasing its bond strength, it pulls of the bitumen layer which is weaker than that bond. To this end remove as much as possible, so there is more contact with the substrate underneath the bitumen. With tiles of that size/type you will most like have to use a thicker bed of adhesive, so make sure it is a low shrinkage product or suitable for the thicknesses required as the standard cement based adhesives tend to shrink and pull bitumen off easier.

This is all based on the floor being a solid screed/concrete etc.

Hi Wayne,

Thanks for the response. The bitumen is is certainly more substantial than just residue left by vinyl tile. The whole of the downstairs is the same sub-floor covered in different rooms with either carpet, lino or self-adhesive vinyl tiles. The carpet has now gone, I'm working on lifting the lino and will remove the vinyl. I was looking at using a single part rapid-setting flexible adhesive after sealing the floor with SBR or similar, how suitable would this be?

Thanks

 

[Wayne_Phipps]

Hi Wayne,

Thanks for the response. The bitumen is is certainly more substantial than just residue left by vinyl tile. The whole of the downstairs is the same sub-floor covered in different rooms with either carpet, lino or self-adhesive vinyl tiles. The carpet has now gone, I'm working on lifting the lino and will remove the vinyl. I was looking at using a single part rapid-setting flexible adhesive after sealing the floor with SBR or similar, how suitable would this be?

Thanks

Hi Again,

I don't personally think sealing with SBR and then using part flexible adhesive would be a permanent solution. The minimum you could do is to remove any lose bitumen/debris , then use one of the levelling compounds that are recommended to use over bitumen, but no more than 6mm thickness. The reason these levelling compounds can work is because they have a low compressive strength and therefore do not pull up the bitumen over time likea standard levelling compound could.

You could then use your single part flexible over the levelling compound to fix the tiles. But I must stress that bitumen substrates do cause a significant amount of failures.