Hi

I am laying a solid oak floor over existing plank. The oak strips are tongue and groove, random lengths, finished, and the manufacturer provides details of three methods of installation:

- Glue to subbase
- Secret nail
- Float

Now, floating seems to be the most manageable option but, apart from the manufacturer's instructions, everything I read says you should never float a solid wood floor.

I don't understand why however. Assuming I leave my 15mm expansion gap around the edges, why should a floating hardwood floor perform any differently to a nailed one in terms of expanding and contracting?

Can someone please explain this to me?

Thanks!

The tongue and groove design dictates whether a floor can be floated. The typical NOFMA T&G profile does NOT allow solid boards to be glued and floated. Another consideration is individual expansion and contraction. IMO, floating a solid is risky. There is a manufacturer who has designed a clip system for his solid floors and that works pretty good.

Hi Gary

I'm not sure about the NOFMA specification, but here are some pics of the T&G.







Why is individual expansion and contraction more of an issue with floating floor than nailed or glued?

Thanks

When one glues solid boards together, they become one big board. Typical aliphatic resin wood glues can be stronger than the wood. IF the environment was maintained at exactly the same temp and RH levels constantly, it may not be a problem. But they usually are not. And individual boards will expand and contract at different rates, depending on the milling (quarter sawn or plain sawn) and the growth rings. All this means is that boards glued together cannot accommodate the expansion and contraction of solid wood boards. And boards glued together risk cracking and splitting. Furniture makers understand this as well and design their pieces accordingly. However, nailing floor boards down does allow for individual movement, as does modern FLOORING adhesives.

Thanks Gary.

Thanks, that was my question also, however, I would like to know more about the clips you refer to

For solid floating wood flooring, with the Junkers clip system...

http://www.junckershardwood.com/