DIY insulating question

Was going to post this in my long-running thread but though it'd get more attention on its own.

I am insulating a secondhand wendy house with polystyrene covered by plywood. All the polystyrene fits into the space between the frame bits with a bit of a gap between the shiplap and the plywood (about 1/8"-1cm or so) and I'm not sealing the plywood so tight it'll not breathe.

The pictures below show the gap at the eaves of the playhouse: I intended a gap there but maybe not this big! Should I cover it a bit more?

For the insulation to work properly it should be as air tight as possible. If the air circulates around the polystyrene it will make it kinda worthless :/

^^^ was about to say the same

Stator said:

If the air circulates around the polystyrene it will make it kinda worthless

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Jonm said:

^^^ was about to say the same

Click to expand...

Thanks I was thinking this too: but if none circulates, condensation becomes a problem! There's an air gap in cavity walls for internal circulation in 'real' houses to prevent this, so I've done the same with this one in the 'complete' places: between two bits of wood is the equivalent of two brick walls in my mind, and I've tried to go with the same sort of ratio of gap:insulation. But this is the fully gappy bit and so, like you say, a bit useless!

As I'm insulating mine more against summer than winter, does it really matter? Hot air rises so the heat from outside will go up and out of the bunnies' way, right? I'm not that convinced, to be honest! I suppose I'm thinking like the ventilation gap in the roofline of a house, to prevent condensation in/on the roof, but then that's down on the soffit, not up by the apex, where this would be in equivalence!