Engineered wood floor plus tiles and UFH

[plumbamateur]

I have a bit of a dilemma. I am just about to create a large-ish open plan living area in my house (36 square metres) and I would like to install a (warm water) underfloor heating system. The existing floor is a suspended wood floor (I should mention house is approx 100 years old) with a large void underneath.

My plan is to remove existing boards and install rigid insulation between the joists. UFH to be installed directly over this using aluminium heat spreader plates. Wood floor nailed to joists directly over this. My questions are as follows:

1. Is engineered wood floor suitable as a structural floor? Usually i believe this is 'floated' over an existing sub floor.

2. I want to tile the kitchen floor area (as well as install UFH). This presents a problem with levels as i'll need a subfloor to tile onto. Can I reduce the height of the joists to that I achieve the same overall level as the new engineered boards where they meet?

I'm a bit confused about what to do here!

Thanks in advance

 

[Dangermaus]

Hi

1. Engineered Wood flooring is definately not suitable as primary flooring. Even if you found some thick enough the ends of the boards would over hang the joists and flex.

2. The joists are the thickness they are as they've been calculated to be strong enough to carry the weight of traffic/furniture etc for that span. So I'd advise against that too.

My advice would be to pull up floor boards insulate, then relay floor boards as a base for the wood flooring and under floor heating. I'd calculate the finished height of this then lay plywood with a thickness to match wood flooring height minus tile depth and 3mm - 5mm for adhesive under tiled area instead of the old floor boards. We usually use a minimum of 1in 25mm ply on wood floors this guarantees the tiles stay down as it removes the flex that usually cracks the adhesive.

Hope that helps

Cheers

 

[plumbamateur]

Thanks a lot Dangermaus - much appreciated

 

[WoodYouLike]

Hi

1. Engineered Wood flooring is definately not suitable as primary flooring. Even if you found some thick enough the ends of the boards would over hang the joists and flex.

Beg to differ. 20mm load bearing wood-engineered boards are as strong as any solid floors that thick, but much more stable - especially when in combination with UFH.
If the joists are not further apart than 35 - 40 cm and every wood-engineered board connects - secretly nailed - with at least 3 joists there is - in our and our Duoplank manufacturer experience - no problem.