help! Bitumen nightmare!

[ditzy]

Hi,
I am installing a solid wood floor. 18mm oak 140mm strip. I have a 70's house, removed old armstrong times to reveal a horrible layer of sticky bitumen. Had contractor over and has told me not to out screed over this, will need to be removed...aargh! worst nightmare. Does it need to beremoved? Apparently my risk if the screed fails in the future. So have been sdvised to hire upright sander and sand the lot (in my newsly decorated living/dining room. help, can alyone offer any advice??
ditzy

 

[WoodYouLike]

Sand bitumen? The friction will make it all sticky and you have the risk of spreading it out instead of removing it.

Here's an article by one of the DIY-not regulars on our FAQ & News site on how to tackle bitumen

 

[ditzy]

hi woodyoulike
not sure if sand bitumen. it feels quite smooth and sticky - like tar. We were recomended by the guy who's screeding to use upright sander but see wat you mean about heat making it tacky. Might just be worth paying them the extortionate amount htey wanted to do it? messy job I'm guessing?
thanks for reply btw

 

[Symptoms]

ditzy - you say the bitumen is currently sticky ("like tar") so if you can't face removing it and won't pay "extortionate" sums to a contractor to do so, then leave it down. Next consider the batten method for fixing the floor down. This is only appropriate if you can accommodate the level of the finished floor being higher by approx 25mm - the thickness of the battens.

I've outlined this method a few times previously on this Forum so maybe do a search for info. But, basically it involves mechanically fixing treated batten to the concrete (using a Hilty nailer), then secret nailing the new T&G boards to the battens; the battens, if you like, act a bit like joists for fixing the floor to. We've used this technique for 25 years.

Post again if you want more info.

 

[Petest67]

Good tip Symptoms.
To remove old bitumen u should look into hiring a shot blaster (newer one preferably - dust free).

 

[geeonegee]

Why dont you use a liquid dpm eg sika mb or lecols excellent pu280 on the bitumen, we do it on a regular basis after uplifting old block floors to seal in the residues, sika mb is a top notch product, if its a small area buy a 5kg unit, its a 2 part product, a into b and mix, a nice thick coat with a 9" paint tray and a short haired roller and job done, if you can paint emulsion onto a wall you can put sika mb down, easy peasy, will take 8 hrs + to dry properly.

dont go down the route of sanding the bitumen.....the builder is having you over and charging you for it as well.

Lecol pu280 is a similar product to sika mb but 1 component so you only use what you need, same application process as with the sika mb but it only takes about an hr to go off, i'd recommend 2 coats.