Thanks to Andy from Workshopshed.com for this guest post about insultation your shed roof.
Everyone knows when it’s cold you put a hat on to keep warm and every house has loft insulation. But when building a shed we typically only have a layer of board topped with felt to keep us warm. My shed was particularly bad as the roof only consisted of some corrugated plastic meaning that even with the heater on it did not keep warm.
Here’s how I retrofitted an insulated roof to my shed with some ideas as to how you might do this yourself.
My shed already had a frame supporting the roof so I knew it would be ok for some extra weight. If your walls are a bit flimsy then you want to consider re-enforcing these before you begin.
In my case, I needed to replace all of the roof so I used tongue and groove for the inner skin. However, it is quite possible to put the new roof on top of the old. The result is a sandwich of wood and insulation with battens for spacing and support.
- Insulation, blocks are easiest
- Timber for battens
- Board such OSB
- Screws, drywall or exterior
- Clout nails
The first step is to remove the existing felt so that you can measure up for the battens. My shed is a bit of a peculiar shape so my batten frame had to match that. Otherwise, you just need a simple rectangle. When using multiple boards, fit cross struts at the places where those boards meet. If you are planning skylights then add extra battens around that area too. The frame can be made up in advance of putting it on the roof. For a large roof, multiple frames may prove more manageable. Place the frame on the roof and screw through from below to secure.
You can now fit the insulation into the frame. For block insulation, this should be straightforward. If you want to use rolled loft insulation then you will need to work out a way of stopping it all sinking to the bottom, perhaps cross wires held with screw eyes?
The top of this sandwich is OSB, if you cut this a bit larger than the frame then you can avoid a gap at the ridge. Otherwise like me, you will need to fit a piece of timber in the gap. Before fixing, I find it useful to pencil on where the battens are located. This makes it easier to ensure your screws will go through the top sheet and secure into the batten. You want the screws to be flush with the board so they don’t rip the felt. I drilled holes for mine but found I did not need to countersink them because the drywall screws do that themselves.
For extra waterproofing an under-felt was added, this is the felt that’s used for house roofs and does not have the stone chippings of regular roofing felt. It was cheaper than regular felt and the stones are only needed on the top layer to protect from the sun. So, to top it all off regular roofing felt was used, held in place with clout nails.
The shed still gets cold in the winter as it’s not constantly heated. It quickly warms up with a fan heater and keeps the heat. This means the fan heater can be turned down or off and the shed is still a pleasant place to work.
You can visit Andy’s website for great posts on his various make projects (includes dragons and 3d Printing), or follow him on twitter.
If you as a sheddie have an interesting build or fix you would like to share with the sheddies then Let me know.