Concrete removal from bitumen

[HH @ 24]

I'm trying to remove a layer of concrete from a bitumen covered floor. I'm chipping away using a chisel and hammer but making very slow progress. I don't want to damage the bitumen underneath as I assume it's there as a DPM. Can anyone recommend a better way to chip it away?

 

[Kearn]

I'm trying to remove a layer of concrete from a bitumen covered floor. I'm chipping away using a chisel and hammer but making very slow progress. I don't want to damage the bitumen underneath as I assume it's there as a DPM. Can anyone recommend a better way to chip it away?

View attachment 10383

More info required - age, construction of house, why you’re removing the concrete…

The bitumen may well have been later laid before concrete as you say, to act as a DPC - question is, whether it actually should be there at all.

 

[HH @ 24]

More info required - age, construction of house, why you’re removing the concrete…

The bitumen may well have been later laid before concrete as you say, to act as a DPC - question is, whether it actually should be there at all.

The cottage is c1800 at the front, and about 30 years old at the back. It's constructed of mainly brick and some stone. The part in the photo, the hallway, bridges the old and new part. The old part of the house has thick bitumen covering the floor (under which is concrete in one room and a brick floor laid directly onto earth in the other). I assume the bitumen was laid later in these two rooms as DPM. The newer part of the house has concrete floors, no bitumen (I assume a DPM was laid underneath the concrete). The hallway in the photo I thought was part of the newer build, but maybe it's on an old footprint hence the bitumen. Under the bitumen is concrete (I broke a hole in the bitumen to see if there might be an original floor of some kind, alas not). The hall floor was covered in very thin vinyl laminate flooring. When I removed it there was this thin layer of concrete under the laminate, over the bitumen (perhaps laid to help the glue for the laminate floor to stick, as don't think all glues stick to laminate). I am planning to lay limestone floor tiles in the hall but there is very little room below the doors for them doors to open, so every mm counts. Removing the couple of mm of this concrete covering is the difference between laying the floor I want and the doors still being able to function, or having to mess around with doors, frames, etc to make them fit a new floor height. I was assuming the bitumen needs to stay but would be happy to remove if not needed... Any advice appreciated. Thanks

 

[malcolm]

Most SDS drills have a setting for hammer mode without any rotation so you can put a chisel in the end. Much faster than doing the job by hand.

What sort of floor covering are you planning? A waterproof coating on the floor will tend to result in water going up the walls instead unless you have a damp course. If there is no existing problem it should be good.

 

[Kearn]

In the old part of your house, technically the concrete and bitumen should never have been introduced. Same goes for the tanking render on the wall in the photo and the tell tell holes where chemicals have been injected. Looks like previous owners had a moisture issue and believed the snake oil salesmen on how to ‘fix’ it.

However, you may not have issues with moisture? If so, you don’t have to go looking for work, but before the effort and expense of laying a new floor I would want to be certain that there wasn’t a moisture issue a being pushed metre or so up the walls or elsewhere where it can escape … You have to assume that the incorrect work undertaken previously was in response to a perceived damp issue at the time, sadly what has been done doesn’t solve it, just hides and displaces the symptoms to appear later…

If height is of importance, I really wouldn’t be worrying about removing the bitumen. Either lay porous stone and grout with lime to allow moisture up and out, or if there is concrete consistently underneath the bitumen, that will be doing much the same thing of blocking moisture movement anyway, so don’t think the bitumen is essential for maintaining the current situation.