Removing fully stuck down underlay

[pandr]

We have sisal carpet on the stairs, and throughout upstairs, which has past its prime, and with a baby on the way, we need something softer underfoot, so we are replacing it with modern carpet.

The new carpet is due to be fitted in two weeks and before then I need to remove the old carpet and underlay. The carper is fully stuck to the underlay (not just around the edges but everywhere) and the underlay is fully stuck to the subfloor (again, everywhere) which is a mix of old floorboards and more modern MDF floorboards.

Pulling the carper up off the underlay is not difficult, however, pulling up the underlay is a different story. The top layer comes off to reveal the black foam inside, which is very well stuck down everywhere. See the attached photo which shows the carpet on the left, and the underlay (top layer removed) on the right, with a portion I have removed to show the floor.

So far I have tried removing the underlay with a heavy duty scraper (http://www.screwfix.com/p/no-nonsense-long-handled-scraper-24/87299) which works, but it hard work and very slow progress, and where the glue is stronger (especially around the edges) leaves some foam which I can't scrape up. I have managed to remove this in the area I have started with a wire brush and even a wire cup drill attachment but it's time consuming.

In addition, there is still glue residue left on the wood - I don't know if this will be a problem for the fitter or not (waiting to hear from them).

I am hoping that someone has a bright idea on how to remove the underlay more easily than the above process as it is going to take me too long to do the whole house this slowly! If scraping is the only option for the bulk of it, what should I use for the glue residue? White spirit? Would that effect the wood? Quite keen to avoid very strong solvents if I can, what with a heavily pregnant wife in the house and no doors yet to contain the fumes!

Thanks a lot for your ideas and advice...

 

[Tigercubrider]

I would have suggested pretty much what you have - I have the same scraper and a bigger one.
Maybe a garden spade?

When fitters replaced our works industrial carpet they had a really messy rotary machine not unlike a cylinder lawnmower that created loads of dust but removed the adhesive.

Possibly an angle grinder (an vacuum) with a paint/varnish disc that will remove material but not damage wood? They are made from a hard nylon

 

[vinn]

FWIW: You should have left the whole job to the fitters.

You can get heavy duty long handled floor scrapers @ many outlets eg tool station or you could hire a floor scraping machine.
With hand scrapers you must keep the blade sharp with a smooth file.

However, once the underlay is off then ignore the old adhesive, the fitters can work over that.

 

[pandr]

Thanks for your thoughts on this.
We had a *fun* weekend with scrapers and managed to get the bulk of it up.

We actually found that with sharp razor scrapers it was difficult not to take a layer of wood off underneath, however a chisel style filling knife did the trick. Time consuming but the fitter came around today and is happy with the finish.

I would have left it to the fitters but with the sisal carpet that has underlay stuck down everywhere, nobody wanted to do it!