1950s bungalow - bitumen damp course

[LaserTam]

Renovating our newly acquired 1950s bungalow. Decorating first room, cut out the carpet round the edge of the room to prep the skirting and lifted the gripper strips. There is a black, now cracked and broken/brittle layer on top of the concrete floor. From some googling, suggests it might be a damp course of bitumen.

So my question is what I can do to repair it? I have not yet lifted the whole carpet, so I may find its not just around the edges that it's cracked, but I'm hoping it's just where the gripper strips were hamered in. Which no doubt that's a completly different project.

[OutInTheShed]

It might also be residue from glued down parquet flooring?

[LaserTam]

I don't think so. It's thicker that I would expect adhesive might be. I'm told that this method of damp course has been known in similar aged houses in this area.

[Rushjob]

I lifted some 1950's parquet stuck down with bitumen, it was about 10mm thick in the thinner bits!

[clockworks]

Same in my 1960's bungalow living room - "finger" oak parquet, laid on thick bitumen.

Fortunately still in pretty good condition, so I just had to refit a few pieces, sand, and apply Osmo.

[TA14]

Apply a self levelling resin waterproofing.

https://www.watco.co.uk/products/watco-roofite-pou... ??

There are lots on the market. Have a study.

[richhead]

Bitumen was use alot as a glue back in the day, especially for flooring, it was cheap and "in the van" makes no sense to have it over the entire floor otherwise.
Get rid of it, your house will thank you.

[Ynox]

LaserTam said:

Renovating our newly acquired 1950s bungalow. Decorating first room, cut out the carpet round the edge of the room to prep the skirting and lifted the gripper strips. There is a black, now cracked and broken/brittle layer on top of the concrete floor. From some googling, suggests it might be a damp course of bitumen.

So my question is what I can do to repair it? I have not yet lifted the whole carpet, so I may find its not just around the edges that it's cracked, but I'm hoping it's just where the gripper strips were hamered in. Which no doubt that's a completly different project.

Floor probably had thermoplastic (Marley) tiles on it originally. This formed part of the damp course on the ground floor. Unfortunately the tiles and the bitumen both contain small amounts of chrysotile asbestos.

I'd honestly just lay a new floor over it and not worry. It's what I did in my 1950s house.

[konark]

A layer of bitumen about 20mm thick was used often as a dpc for floors in the early 1950s. It does crack and is laid so it is the actual floor finish so any nails or screws go right through it to the wet concrete below. It should join the dpc in the walls which is also at floor level.

[Pistom]

Just beware of asbestos content. This bitumen type material was used and asbestos was sometimes part of the makeup. Not a problem if undisturbed, very much a problem if you're thinking of taking it up.

If you're going to do anything with it, send a piece off for analysis so you know what you are dealing with.

[wolfracesonic]

If it’s over an inch thick, it’s probably mastic asphalt and nothing to do with parquet flooring. A bit of reading here mastic asphalt, it can be repaired or ironed back down if it’s gone wrinkly, ironically it’s roofing contractors who probably use it most nowadays, Aluminati on here will know about.

[LaserTam]

Update after a bit more investigating under the carpet. The black brittle things are actually tiles, maybe 5mm think, with some adhesive underneath. Also, the tiles and adhesive do not go under the skirting. So, I think it's definitely not any sort of DPC. I will be laying the flooring directly in top.

Thanks for replies.

[Lotobear]

LaserTam said:

Update after a bit more investigating under the carpet. The black brittle things are actually tiles, maybe 5mm think, with some adhesive underneath. Also, the tiles and adhesive do not go under the skirting. So, I think it's definitely not any sort of DPC. I will be laying the flooring directly in top.

Thanks for replies.

Many of those old 'Marley' type tiles from that era contained asbestos fibres, along with the adhesive, so worth taking a bit of care

[LaserTam]

Lotobear said:

Many of those old 'Marley' type tiles from that era contained asbestos fibres, along with the adhesive, so worth taking a bit of care

[RGG]

It was a "thing" when renovating for a bitumen floor to be floated onto "usually" a damp floor or just to level out an uneven floor.

A friend had bitumen flooring in first floor bedrooms to level out the floor in a listed property - approved by the "listed people".

Any renovation could be done with more bitumen being applied.

[Aluminati]

wolfracesonic said:

If it’s over an inch thick, it’s probably mastic asphalt and nothing to do with parquet flooring. A bit of reading here mastic asphalt, it can be repaired or ironed back down if it’s gone wrinkly, ironically it’s roofing contractors who probably use it most nowadays, Aluminati on here will know about.

Entirely correct, and was , and probably still is the best tanking solution. Sadly, a dying art, even though it’s 100% recyclable. We still use it for Heritage work ( Mate is on Tower of London currently) anyway, I waffling…