Hello house building experts,
I have been silently following for some time and would like to ask my first question.
We are currently planning a two-story house with a shed roof. The roof will cover a base area of 10.75m x 8.40m (35.3 ft x 27.6 ft) plus a 1.0m (3.3 ft) continuous roof overhang, resulting in a total roof area of 130 m² (1,399 sq ft). The roof is oriented approximately 10 degrees to the south, sloping upwards toward the north, and will be constructed as an insulated roof without an additional intermediate ceiling or attic space. Our structural engineer has designed the roof with bitumen roofing membranes covered by slates. His reasons are the low costs and the reduced noise during rain compared to metal roofing. However, we are now questioning whether bitumen membranes make sense in terms of durability.
We are also planning a photovoltaic system, and ideally the roofing should last at least as long as the solar panel system so that replacement can be done simultaneously. Flat roofs are often made with bitumen membranes, so what are the arguments against using it here? Is bitumen an unsuitable substrate for photovoltaic systems? What do the experts recommend?
- Bitumen membrane as currently planned
- Synthetic membrane/EPDM membrane (I was recommended the Alwitra membrane)
- Metal roofing (corrugated or standing seam?)
- Tile roofing (probably not practical given the low roof slope)
Like most homeowners, we are of course very concerned about not having excessively high construction costs due to the current price increases.
Best regards,
Kevin
I have been silently following for some time and would like to ask my first question.
We are currently planning a two-story house with a shed roof. The roof will cover a base area of 10.75m x 8.40m (35.3 ft x 27.6 ft) plus a 1.0m (3.3 ft) continuous roof overhang, resulting in a total roof area of 130 m² (1,399 sq ft). The roof is oriented approximately 10 degrees to the south, sloping upwards toward the north, and will be constructed as an insulated roof without an additional intermediate ceiling or attic space. Our structural engineer has designed the roof with bitumen roofing membranes covered by slates. His reasons are the low costs and the reduced noise during rain compared to metal roofing. However, we are now questioning whether bitumen membranes make sense in terms of durability.
We are also planning a photovoltaic system, and ideally the roofing should last at least as long as the solar panel system so that replacement can be done simultaneously. Flat roofs are often made with bitumen membranes, so what are the arguments against using it here? Is bitumen an unsuitable substrate for photovoltaic systems? What do the experts recommend?
- Bitumen membrane as currently planned
- Synthetic membrane/EPDM membrane (I was recommended the Alwitra membrane)
- Metal roofing (corrugated or standing seam?)
- Tile roofing (probably not practical given the low roof slope)
Like most homeowners, we are of course very concerned about not having excessively high construction costs due to the current price increases.
Best regards,
Kevin
Kevke93 schrieb:
... The only question left is how to fix the photovoltaic system. ...For flat roofs, there are mounting systems that do not penetrate the roofing membrane. These are simply elevated and secured with appropriate ballast weights. They are available as plastic trays designed for the standard module size. These trays are then filled with gravel, sand, or water (depending on the system and site conditions). Alternatively, aluminum profile constructions can be used with paving slabs or similar as ballast. I would always recommend placing thick EPDM strips under the systems to prevent slipping and provide additional mechanical protection.The weight should be carefully calculated, since a photovoltaic module of nearly 2m² (21.5 sq ft) acts like a sizable sail!
B
Benutzer20019 Apr 2022 16:29Kevke93 schrieb:
The only remaining question is how to fix the photovoltaic system.For flat roofs, it is usually installed without damaging the roofing membrane. There are various systems and providers for this (these use ballast weights). The panels are then mounted at a lower angle, which eliminates shading issues, allowing the panels to be placed closer together. They can also be mounted with opposing tilts (east-west), which improves stability against wind (which usually comes from the west, occasionally from the east).