karndean korlok prep

[kp00110]

Hi

We are putting down some karndean korlok herringbone floor. It is a 1930s timber suspended ground floor, with original 18mm floorboards on joists and dwarf walls construciton. The floor is well ventilated and completely dry. We have made repairs in some areas so is now solid and all screwed down very securely.

The next stage is plywood and I would just like to check what thickness is recommended? Most say 6mm but would much rather get thicker if it will give the better and longer lasting finish. Is it absolutley critical to get flooring grade ply such as sp101 i have read, or is thickness the governing factor?

Once decided will get the plywood installed and screw down at recommended centres

If the floor and ply are then level within the tolerances (5mm over 3m) is that sufficient for install above? I have seen about prepping the plywood joints which isnt an issue, but would much rather get the thickest and best ply to get the best floor level and prep rather than have to apply liquid products to the whole room just from a skills perspective

 

[kp00110]

we are getting 9mm sp101 - I know we stagger joints - are we okay to butt up tight or leave small gap

 

[crazydaze]

Leave a small gap to eliminate squeaking, 9mm SP101 will be perfect. Be careful and allow as much expansion as you can get away with.

 

[kp00110]

ok thanks and then small gap we can place feather edge from Ardex, same for screwholes, i have read elsewhere on this forum. Hopefully goes well

 

[dazlight]

As you are going with a floating floor 6mm will be fine. You don’t need sp101 just a decent hardwood plywood. You won’t need feather finish either as not gluing to the ply.

 

[kp00110]

Okay so to be sure, don't need to Feather finish the holes in ply from fixings or small ply joints, as flooring should float over those and not reflect up?

Out of interest why is it different between glue down and floating floors? Are glue down much thinner then?

 

[dazlight]

One is glued to the sub floor and the other has a click system.

We don’t Fit many clicks as I don’t rate them. Sunlight can make the edges raise up and the subfloor has to be completely flat.
most glue downs are 2.5mm and you can lay in more designs.