Concrete base for a wood floor outside


We live in the Caribbean and we are in the process of building our home – an average sized family house 2800 sq ft. concrete structure. However I have always wanted a wooden floor in the fanily room and rather than the usual concrete patio (covered with ceramic or clay tiles) I wanted a wooden deck. Somewhere along the lines, this evolved into a covered deck, then a wooden floor over a concrete patio. Now the builder is telling us that a wooden floor would be impossible at this stage (the concrete has not been poured for the floor as yet). I would have to use parquet tiles or planks in the family room.

My question: Regarding my patio (once deck) is there any type of wooden floor that can be accomodated ove a concrete base outdoors? We will be importing greenhart for Guyana for use elsewhere in the house – is there a solution that would utilise this or similar hardwoods?




Dear Gail

I’m not sure I understand your question about what floor is going to be inside or outside, maybe in such a climate as yours it may not matter as long as it is sheltered from the rain. But a wooden deck is different in structure than a wooden floor. The wood in the deck can stand to get wet and because the boards are spaced 1/4″ apart they can expand a bit individually and not buckle next to the other boards. Also there is some space under the deck to allow the boards to dry out so they don’t rot. A wooden floor by it’s nature is usually a fitted tongue and grove planks,and doen’t have room for much expansion. If a wooden floor gets wet it will buckle and raise off the subfloor to make a great hump. Also a wooden plank floor will not dry properly and will soon rot.

The closest to an outdoor floor I could suggest is to go a head and pour the concrete and once it has cured for about 2 months lay a framework of sleepers or screeds on the concrete. These can be 2″ by 4″ boards laid on their side made out of pressure treated wood. Then on top of this lay a decay resistant wood like ipe’. You should leave 1/4″ gaps between the boards and a 1″ space around the edge to allow moisture to escape. It would be a good idea to have drain channels in the concrete in case some rain flooded in. Ipe’ is a good decking material and is very hard and good looking, just let it age naturaly, don’t try to finish it with a varnish.

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As always your Most humble servant, Joseph, the Wood Floor Doctor.-