Hi

helping gf do garden, currently has a sound concrete shed base.

? Presumably tongue and groove is better than overlap.
? Presumably the panels etc just screw together then roof the lay felt

? Big issue is understanding the floor – they all appear to be OSB Resin Board type stuff. Does this go straight onto the concrete.

? I’ve had advice:
A – concrete base should be slightly smaller so water drips off shed AWAY from base – which sounds good to me
B – shed base should be bigger – to stop sag etc

Thanks

if you can afford it get one with a proper wooden floor and roof as it will last a lot longer

Hi, thickeer timber is generally better whether T&G or overlapped. Yes it is normally just a case of screwing together the pannels and laying roof felt. Lots of sheds use OSB floors with battens under to hold off floor/base. You could intall it on tannalised supports 2×4 or similar layed 90′ to battens on shed base to hold floor battens clear of base and reduce chance of rotting/laying in water on base.

All depends how much you want to spend really.