Corrugated Shed Roof insulation

Sleamhain · 27-10-2025 07:05PM #1

Hi,

Looking for the some methods to insulate my shed roof. It soaks with condensation this time of year and drips all over my workshop.

Its just metal corrugated steel roofing sheets over timber at the moment. It's draughty (I e. Well ventilated!).

The options I have in mind I are as follows

1. Replace roof with corrugated sheets with drip stop (no insulation)

2. Add insulation (rigid or rockwool) inside roof between timbers. (6" of depth available)

3. Replace roofing sheets with a corrugated sheet that is insulated.

Option 1 I don't think is a runner, if going to that effort I may as well just insulate.

Option 2 - I don't know if this is a good idea. Will I just end up with condensation behind the insulation and a damp mouldy mess to deal with? Would I insulate over the timbers or up to the timbers (thermal bridging?) Do I need to seal gaps between insulation boards?

Option 3 - Costly, and don't know how I treat the edges of the roof where is facing out at the gable end? How do you seal the insulation at the edge of the roof from rain getting in?

Anyone with any tips or advice, it would be much appreciated. It's about 50m sq of roof area

Picture of roof added below

Thanks in advance!

tabby aspreme · 28-10-2025 10:22PM

Have you looked into the spray on foam, I've seen a good few similar sheds done with it

Calahonda52 · 29-10-2025 12:35AM

What I have always done here is pot chicken wire across the beams and then felt over that and then the sheeting

Condo is caught by the properly overlapping felt and runs off.

The spray option has two risks, moist will be retained against the sheeting and possibly rust it over time.

treatment around timbers and eaves is both tricky and problematic

Corrugated Shed Roof insulation

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