Insulating A Shed Dormer Roof

Hello i have shed roof dormer that ties into the roof below the ridge line so venting is a challenge.

Insulating a shed dormer roof.

Insulating a shed roof is typically done using insulation below the roof deck and between the rafters. Most building codes allow for unvented roof construction. Place the plywood onto the roof of your shed in such a way that it acts as sheathing for the roof s structure. The joists are 100mm deep.

However creating a vented roof gives a thermal separation between the roof and the conditioned heated and cooled spaces of the house so the sun baking on your metal roof won t over stress your air conditioning in the summer and snow will melt off your roof slower in the. Each roof style has some different insulating challenges. Care is needed to ensure that there is sufficient ventilation space between the underside of the roof deck and the top of the insulation. Now to the actual question how can you insulate a dormer roof.

Spray a layer of closed cell polyurethane foam on top of the roof sheathing supplemented by a layer of air permeable insulation below and in direct contact with the roof sheathing. First you do not have to create a vented shed roof. The minimum rating of r38 in a roof requires some creative planning in the roof design of a new shed with 2 x6 minimum roof construction. The shed dormer is currently under insulated with a vent for air to enter but not to exit and i have moisture issues inside.

Make sure you place the plywood at a right angle to the joists of the roof. In areas with a cold climate part of the year r38 is the minimum and r50 is recommended. I m in new hampshire at 1200ft above sea level climate zone 6a i believe. 1 the first method is to use rigid insulation.

Spray a thick layer of closed cell polyurethane foam on the underside of the roof sheathing. You can use the oriental strand board osb instead of plywood. A roof is like a hat. For a heated shed warmer air inside rises and can have a relatively high moisture content.

It keeps everything under it warm. The cavity was formed betwee. Initially i was going to put down 50mm celotex in between the joists which would leave a 50mm air gap. To insulate an existing dormer we outline three of the more common methods below.

The rigid insulation method requires the utilisation of 150mm thick insulation in between the rafters along with a 50mm air gap in order to avert cold bridging. Step 1 install and nail the plywood. Most of the roof space is well insulated except the flat dormer roof.