I've Insulated My Loft, But Now I Have Condensation. What Went Wrong?

This is a very common issue. By laying thick insulation, you have made the loft space above it much colder. The warm, moist air from your house can still find its way into the cold loft, and when it hits a cold surface (like the roof felt or timbers), it condenses. The most likely cause is that you have blocked the ventilation path at the eaves (the edges of your roof). You must ensure there is a clear air gap for ventilation to flow through the loft and remove this moisture.

I've Heard Spray Foam Insulation Can Cause Problems Getting A Mortgage. Is This True?

Yes, it can be a significant issue. Some mortgage lenders are hesitant to lend on properties with spray foam insulation, particularly the "closed-cell" type. The concern is that the foam can trap moisture against the roof timbers, hiding potential rot, and can make it difficult to inspect the condition of the roof structure. If considering spray foam, it is crucial to use a reputable, fully certified installer and check with your mortgage provider beforehand.

What Does It Mean To Insulate "Over, Between, And Under" Rafters?

This describes the different layering techniques used in a "warm roof" to achieve high performance. Between Rafters: Insulation (usually rigid board) is cut to fit snugly between the timber roof rafters.Over Rafters: A continuous layer of rigid insulation is laid over the top of the rafters, before the tiling battens are fixed. This is very effective at preventing thermal bridging through the timber.Under Rafters: A layer of rigid insulation is fixed to the underside of the rafters, just behind the plasterboard. Often, a combination is used, such as insulation between and under the rafters, to meet modern thermal requirements.

What Is Rafter Level?

When we mention 'rafter level' we are referring to the structural timbers that support the pitched roof. Joists are the flat horizontal beams at ceiling level.

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