walnut wood floor - sub floor preperation....insulate or not

[Tadge]

Hi all,

I'm planning to fit walnut floor on my ground floor of my house. The existing screed (30mm) is uneven so will be taking up back to the concrete oversite. There is no damp proof membrane other than bitumen painted onto the concrete oversite before the screed was laid. I cant raise the floor any higher so have to ensure the finished floor level does not go higher than 30mm. My options are, once the screed is removed,

1 - install DPM on concrete, install battens to level, infill inbetween battens with 25mm or 30mm kingspan and then secret nail the flooring to the battens. The pros are that I will have an insulated floor but may have problems if the wood I buy has shorter lengths which the battens may not sufficiently support.

2 - Re- screed (30mm) to level the floor up and then prepare the new screed after drying with Sika Primer MB. This will stabilise the screed and provide a moisture barrier. I can then glue the floor direct to the sealed screed and have a solid floor. There will be no insulation using this method.

I'd pefer to have a solid glued floor rather than nailed, but which method is best? Will I really notice a difference if there is no insulation compared to 25mm insulation?

Walnut is expensive so I dont want any moisture (or other) problems. Do my ideas sound feasible?

Thanks in advance for your help.....

 

[WoodYouLike]

Both options sound feasible.
Some remarks though: make sure your battens are at least 75mm wide so you secret nail properly. As for shorter lengths: as long as every board connects with at least 3 battens you're fine (plus the underlayment works as extra 'support'). You don't need to end a board exactly on a batten.

As for screed: rule of thumb - every inch of concrete/screed takes at least 30 days to dry out properly before you can install anything to it.
Use flexible adhesive to glue the floor down and use the correct notched trowel.

 

[Tadge]

Thanks for the response, do you think I'll feel a diffeerence between the insulation method or not? I'd prefer to glue to screed but not sure if 25mm insulatiuon will make a huge difference. Thoughts?

I assume the sika primer levels and creates a moisture barrier, will this be adequate moisture barrier if I cant guarantee the existing floor dpm? Ive dug down and there is, from the ground up, 600mm oversite, 100mm concrete (painted with bitumen, 30mm screed (painted with bitumen30mm)

So, plan is if I remove existing screed and re bitumen the concrete then re screed then appy sika then glue down with flexible adhesive.

What do you think?
Thanks