Wooden conservatory flooring

2 Nov 2007
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Newcastle upon Tyne
United Kingdom
I am in the process of laying a floor in the conservatory over wooden joists at 400 centres.
I was going to use waterproof 18mm T & G chipboard and lay a laminate or engineered wood flooring over the top.
Is it better to use second hand floorboards then cover with ply,22mm T&G/or thick plywood or any other suggestions.
The floor level drops 40mm from kitchen to the conservatory so I have to raise the floor level by quite a bit..How do you finish this off? do you use a plinth??
Its took me all summer to build this conservatory and dont want to put down a poor floor after all my effort.
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yarpa - first question, will the conservatory have lots of plants; if yes, then it'll have high humidity levels (it'll be a bit like a tropical plant house). If it's only going to be used as an extra room, say a dining-room then clearly humidity levels will be much lower. This has an influence on the type of flooring you might choose. Current wisdom suggests engineered wood (not solid) in high hum areas, although many would suggest no wood at all in places like this (use tiles, etc.). I am more open-minded on the issue and take a position based on my own experience, namely, solid maple, secret nailed to battens (joists) in conservatory (& bathroom & kitchen) layed 25 years or so ago, and it hasn't shifted and still looks good; my conservatory houses plants.

Why not use thick flooring, secret nailed to your joists and forget about sheeting below. If you do decide to use sheet material steer well clear of chipboard whatever you do, if you have to use sheet material use ply.

Either a step (plinth) at the floor drop, or a short, shallow angled ramp.
Thanks for the advice.The room will be full of plants so will have a high humidity.Solid maple might be a tad expensive for a 5mx4m area so I think will go for plywood and engineered wood .
When you say thick flooring do you mean thick planking??
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yarpa - my reference to 'thick' was in respect to real wood at about 20mm or so thick.

As you are going for ply under engineered wood use 18mm exterior- grade ply (I'd screw this to the joists - others may have alternative solutions). If you have a void below the joists I'd be tempted, if you haven't already done so, to install sub-floor ventilation (air bricks). A quick way of doing this, without resorting to the bolster & chisel, is to obtain some circular soffit vents from your local builders merchant then drill holes through any dwarf wall (below floor level) with a core drill of the appropriate size for the vents. Insert the vents in the holes (these vents are meshed up to keep bugs & vermin out.

Your 40mm drop will now be reduced to 22mm 'cos of the ply; it'll be reduced even further by the thickness (??) of your engineered stuff, so maybe the best solution for the 'step' would be a chamfered timber strip to match the flooring.

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