Solid Oak Floor installation on Asphalt/Bitumen Floor...

[Woody3]

The floor construction of our property at the moment consists of flagstones, topped of with a lovely coat of asphalt/bitumen. Gutted!

We want to install solid oak floors on top of the bitumen and have been advised to cover the area first with 18mm/22mm plywood (already purchased).

Now, should we put underlay between the bitumen and plywood, something like this:

http://www.ebay.co.uk/itm/270893914989?ssPageName=...

Then lay the solid oak floor directly on top of the plywood? Would you nail or glue the oak to the plywood? How would one fix the plywood to the bitumen? Make it a floating floor?

Or could I just lay the plywood on top of the bitumen, with a "standard laminate" underlay sandwiched between the oak and plywood?

Many thanks

 

[Woody3]

Anyone?

 

[billybuntus]

I would personally of laid a non breathable membrane across the floor then battened the floor with 2" wide x 1" roofing lathes (treated).

Then filled with inch kingspan and laid your floor across. The beauty of using battens is that you can easily pack them to suite to get them level and they are very cheap.

Plywood will be a nightmare to level (working with large sheets). Good luck!

 

[Andrew Bodenham]

Woody3,

I'd be looking to attach the ply securely to the bitumen/flag floor. How thick is the asphalt layer? When I laid a similar construction on a concrete floor I used countersunk multi-monti screws (masonry screw that need no plugs) to secure the ply. My oak (10mm thick oak overlay boards) were then glued to the ply, with additional pin fixings through the tongues to keep everything in place whilst the glue set.
I used a 3mm combined dpm and foam underlay between the ply and the subfloor, which helped deal with some local roughness on the concrete - other areas were made up with leveling compound.
Hope this is of some help.

 

[88v8]

Oak woodblock was often laid and bedded direct in asphalt. If that's what you're laying, perhaps just need some liquid asphalt.

Ivor

 

[Moo]

The floor construction of our property at the moment consists of flagstones, topped of with a lovely coat of asphalt/bitumen. Gutted!

When I read this first sentence I assumed that the rest of the post would be a question about how to remove the bitumen to reveal the flagstones.
Have I missed something?

 

[Woody3]

Thanks for all of the replies.

Andrew - I think that's how we are going to construct the floor. Thanks for the tips especially RE: the screws! . Just trying to work out if to go Solid or Engineered Wood. A lot of what I've read on the Internet points in the direction of Engineered, which I was initially surprised about.

BB - if I hadn't already bought the plywood, the roofing laths sounds a good idea. The floors are pretty level in all fairness, but if I'm struggling getting a decent level, then I'll try this route.

Moo - as much as we'd like to get rid of the bitumen/asphalt, unfortunately/fortunately it's doing a very good job of stopping any damp coming through. In an ideal world, I'd take the bitumen up along with the flagstones (assuming all the areas are covered by flagstones) and then relay them on top of a DPM. However, our pockets aren't quite deep enough to run this risk . You've got me slightly more intrigued though now! :|

 

[Me!]

Would it be possible to lift all the flagstones and turn each of them upside down to give you a waterproof surface on the underside and a natural stone surface on the top?

 

[Moo]

it's doing a very good job of stopping any damp coming through.

Or, to put it another way: "it's doing a very good job of trapping the damp and not allowing it to evaporate"

You really don't need a DPM, honestly.
If you can just clean up the flagstones you'll find that damp won't be a problem. As I've said here before, umpteen times, we lived for many happy years with flagstones in the hall and pamments in the breakfast room, all laid on earth, and once we'd got rid of the cement screed and other nasties they remained dry as a bone, needed minimal care, and were much admired.
I'm sure you could find lots of other things to spend your hard-earned cash on!!!