If you have a new account but are having problems posting or verifying your account, please email us on for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact

Insulating a steel shed.

  • 02-12-2021 6:12pm
    Registered Users Posts: 10,248 ✭✭✭✭

    Hi all,

    I have just purchase a steel shed with the non drip condensation roof.

    I am looking to insulate it though (not just the roof the walls also), and then put plywood over the insulation (and screw the plywood into the tubular steel frame using tec screws).

    What Do people recommend to insulate?

    Foil backed foam board/ foil front and back/spray foam?

    I will be wiring and heating (the heating won’t be on all winter just whenever I have to escape the house!).


  • Registered Users Posts: 1,726 ✭✭✭poker--addict

    Also curious about this. What was the cost of buying it without the insulated walls .v. with?


  • Registered Users Posts: 10,248 ✭✭✭✭tom1ie

    It’s a 5m x 3m shed and it cost 3k. Ordered it in March only got it yesterday!

  • Registered Users Posts: 39,181 ✭✭✭✭Mellor

    You’ll need a ventilation gap between insulation and steel outer layer.

  • Registered Users Posts: 2,300 ✭✭✭martinn123

    In my experience, a number of issues here, that you may have discussed with the Shed Co at time of purchase.

    As it appears the Co are one who believe Condensation only occurs in the roof, and so no non-drip on the walls, possibly explains the lack of advice.

    The frame of the shed, is obviously in contact with the outer sheeting, you now cannot get insulation between the frame and the outside sheets, so you cannot eliminate the cold bridge, condensation will occur at these points, especially along the length of the ridge.

    The non-drip fabric is designed to absorb moisture from the air, at the same time there is ventilation at the top of the wall, which changes the air, and dries out the fabric, this is a continuous process, so for example in wet winter weather the fabric may be damp to touch, thats fine, the ventilation will dry it out.

    If you cover up the fabric, it will continue to absorb moisture, but you will have cut off the change of air, and it will saturate, dampness will travel through your insulation and timber lining, from the outside, in.

    The answer, although not ideal, is to burn off the fabric, use a blow-torch, this is what the Shed Co does in the factory if they are fitting insulation, but they can get it between the frame and external sheeting.

    I'm afraid you have purchased a storage unit, and now want to convert it to something that's it was not designed to be.

  • Registered Users Posts: 33,856 ✭✭✭✭listermint

    Often wondered if the self adhesive insulation used in boats would be good for this application.

  • Advertisement
  • Registered Users Posts: 10,248 ✭✭✭✭tom1ie

    Ok so what about, for the walls, adding insulation to the steel panels that is deeper than the frame of the shed. The insulation can then extend over the tubular bars.

    Plywood can then be screwed to the tubular bars using Tec screws which holds the insulation in place.

    Failing this, is there not a vapour barrier I could purchase to put between the steel and the insulation?

    Also what about spray foam?

  • Registered Users Posts: 530 ✭✭✭mike_2009

    I did my 3m x 3m steel shed last year. 30mm foil backed insulation (ballytherm or equivalent) for floor. Fibran XPS 40mm for walls in between steel frame. Then 12mm ply on walls & floor and 6mm for ceiling (sags a bit so watch out!). Screwed into steel frame. I think I add some wood to the steel frame a little bit to fit wiring etc behind the plywood. I fitted vents into the ply ceiling. Use sprayfoam to seal any big gaps at corners before the work. Painted the floor with anti slip paint. Has been dry all year - XPS won't soak up any moisture - the foil backed floor - same. Thought I took photos but can't find them currently.