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- 10 Mar 2017
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Hello, this type of thing has been answered before but the joists in my garage run side to side, as opposed to front to back so it leaves me with a slightly different problem.
My single garage is in a block of garages and is made up of a single skin of breeze blocks. It has a flat felt roof laid upon a bed of wooden boards. There is no insulation on either the walls or the ceiling. Basically I get condensation building up on the inside of the roof in cold weather which leads to some mould build up. I'd like to install some insulation boards between the joists so that the inside of the roof doesn't get so cold and therefore helps to limit condensation. My worry is that there won't be adequate ventilation between the insulation boards and the wooden boarded ceiling.
A few years ago I added vents to the front of the garage and a couple of air bricks into the back wall (see photos). This provides some ventilation in the garage but not enough air flow between the joists. The problem is the joists run side to side so they inhibit air flow through the garage.
I've thought of two possible solutions:
Solution 1: Install insulation boards between the joists and pack them right up snug to the ceiling with no air gaps.
Solution 2: Drill some ventilation holes through the top of each joist (some advice on spacing/how many/how big would be helpful so as not to compromise the strength of the joists!), then install insulation boards in-between the joists leaving a cavity above and finally fit boards underneath the insulation. This should create a flow of air from the air vents at the front of the garage to the air bricks out the back (see my simplified sketch if it helps to visualise this). I might not even bother putting the boarding up if the insulation boards alone will suffice.
Would either of these solutions work? And even if I make the ceiling warmer, would I just be shifting the problem to the walls as they would be the next coldest spot in the garage?
My single garage is in a block of garages and is made up of a single skin of breeze blocks. It has a flat felt roof laid upon a bed of wooden boards. There is no insulation on either the walls or the ceiling. Basically I get condensation building up on the inside of the roof in cold weather which leads to some mould build up. I'd like to install some insulation boards between the joists so that the inside of the roof doesn't get so cold and therefore helps to limit condensation. My worry is that there won't be adequate ventilation between the insulation boards and the wooden boarded ceiling.
A few years ago I added vents to the front of the garage and a couple of air bricks into the back wall (see photos). This provides some ventilation in the garage but not enough air flow between the joists. The problem is the joists run side to side so they inhibit air flow through the garage.
I've thought of two possible solutions:
Solution 1: Install insulation boards between the joists and pack them right up snug to the ceiling with no air gaps.
Solution 2: Drill some ventilation holes through the top of each joist (some advice on spacing/how many/how big would be helpful so as not to compromise the strength of the joists!), then install insulation boards in-between the joists leaving a cavity above and finally fit boards underneath the insulation. This should create a flow of air from the air vents at the front of the garage to the air bricks out the back (see my simplified sketch if it helps to visualise this). I might not even bother putting the boarding up if the insulation boards alone will suffice.
Would either of these solutions work? And even if I make the ceiling warmer, would I just be shifting the problem to the walls as they would be the next coldest spot in the garage?
