ᐅ Challenges with interior roof insulation and later photovoltaic installation?
Created on: 2 Jul 2020 14:24
H
handyanerH
handyaner2 Jul 2020 14:24Hello
In an existing property built in 1972, the roof is not insulated at all. The concrete roof tiles are also original and, according to an expert, are expected to last about another 5-7 years. The rafters are approximately 10cm (4 inches) thick and 14cm (5.5 inches) deep. It is a gable roof with an east-west orientation.
There are two main things I want to do with the roof:
1. Insulate it
2. Install a photovoltaic system
If I have the roof insulated from the inside with blown-in insulation, it will cost me around 10,000 euros.
When it comes to installing the photovoltaic system, I would like to replace the roof tiles at the same time to avoid setting up scaffolding more than once.
From an economic perspective, does it make sense to insulate the roof from the inside, or will the roof need to be removed or damaged during the installation of a photovoltaic system? With blown-in insulation, the rafters remain accessible from the outside and are not covered by a vapor barrier membrane.
In an existing property built in 1972, the roof is not insulated at all. The concrete roof tiles are also original and, according to an expert, are expected to last about another 5-7 years. The rafters are approximately 10cm (4 inches) thick and 14cm (5.5 inches) deep. It is a gable roof with an east-west orientation.
There are two main things I want to do with the roof:
1. Insulate it
2. Install a photovoltaic system
If I have the roof insulated from the inside with blown-in insulation, it will cost me around 10,000 euros.
When it comes to installing the photovoltaic system, I would like to replace the roof tiles at the same time to avoid setting up scaffolding more than once.
From an economic perspective, does it make sense to insulate the roof from the inside, or will the roof need to be removed or damaged during the installation of a photovoltaic system? With blown-in insulation, the rafters remain accessible from the outside and are not covered by a vapor barrier membrane.
K
knalltüte3 Jul 2020 17:38From a technical perspective, insulation is always more effective when installed on the exterior side. In this case, an energy-efficient solution would be a combination of continuous insulation above the rafters plus insulation between the rafters (blow-in insulation / mineral wool, etc.), since 14cm (5.5 inches) is not much by today’s standards. Additionally, continuous insulation above the rafters creates a smooth surface for the new roof covering.
For every situation, there are options to attach the photovoltaic system (rafter anchors). The solar installer or roofer will be able to explain these details to you in advance. Regarding the roof tiles, I currently lean towards metal replacement tiles. They are likely technically superior and overall more cost-effective than modifying traditional tiles to secure the rafter anchors for the photovoltaic system.
Appropriate cable penetrations (e.g., 50mm (2 inches)) for photovoltaic cables are usually installed and sealed airtight by the roofer. Roof vents can be replaced with low-profile vents and covered with photovoltaic panels. If a satellite antenna is present, it should be relocated to the gable at the same time to avoid potential shading.
For every situation, there are options to attach the photovoltaic system (rafter anchors). The solar installer or roofer will be able to explain these details to you in advance. Regarding the roof tiles, I currently lean towards metal replacement tiles. They are likely technically superior and overall more cost-effective than modifying traditional tiles to secure the rafter anchors for the photovoltaic system.
Appropriate cable penetrations (e.g., 50mm (2 inches)) for photovoltaic cables are usually installed and sealed airtight by the roofer. Roof vents can be replaced with low-profile vents and covered with photovoltaic panels. If a satellite antenna is present, it should be relocated to the gable at the same time to avoid potential shading.
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