Hello,

We're considering laying so-called solid wood flooring on our ground floor - placed on top of that green cellulose board stuff which would be on top of the existing mix of concrete and suspended timber.

We spotted some nice pine floorboards at B&Q, but the chap there said we'd get condensation if we did as I've described. He then said it would be ok if we bought those small multi-sized tongue & groove solid wood floor bits they sell. Now I'm confused; wood is wood surely, and in terms of condensation behaves similarly whether in 6 foot or 1 foot lengths?

Is it also the case that we need to lay the wood at 90 degrees to the original floor boards? This is inconvenient, as obviously we'd like to follow the joists for nailing in such flooring.

Any help/opinions much appreciated.

Paul

You can lay your new flooring in any direction that you like over the top of existing.

If laying in a hallway you should lay these boards away from you i.e. not across a narrow walkway. This will make your hall more spacious and the boards less vulnerable to wear and tear. I personally wouldn't go for pine as too soft and easily damaged - use a hardwood such as french oak. You can get this for about £20sqm if you shop around. Also leave for about 3 weeks in the room where you are going to lay it before securing to floor.

I suspect the sales man was pointing you in the direction of "engineered" flooring, this is solid wood in the sense that it is constructed of either ply with a veneer finish or a cheaper wood such as havea with either a veneer or stained to match the real thing. If you have any doubt go for the ply with the veneered face, it's much easier to lay and more stable in less than perfect conditions than proper tree wood.

It sounds to me as though you have a mixed floor of concrete and suspended timber, be careful as these can react differently over the seasons and very often be different in level with a lip at the edge of the concrete, often by only a few mm but enough to have an effect, particularly if the concrete is solid with no damp proof (pre 60's).

Real wood (not ply) shrinks mostly over its width, ie across the grain, for this reason the boards should be laid parallel to the longest side. Regarding shrinkage, this is common to the vast majority of wood that can buy, modern processing involves heating the wood in an oven to reduce the moisture content down to 15% to 8%, this doesn't however fully season the wood, over the next year or so the cellular structure of the wood slowly contracts. this will show itself in a couple of ways depending on the wood, you will definitely find the wood shrinking sideways, but you may also find that the grain stands out more particularly in way of knots.

Try to lay the floor on an average day, and seal it as soon as possible with one primer and three finish, having seen a hall floor laid on a very dry day then left to soak up atmospheric humidity through a very wet month before sealing lift by 25mm over 1.2m this is really vital.