ᐅ Renovating an older building: which insulation measures are mandatory?
Created on: 26 May 2017 09:11
A
Altbau1930
Hello everyone, I need your advice because I’m having trouble understanding all the energy requirements for old houses.
We will start renovating a house built in 1930, which has been in the family. The roof will be completely replaced (there was woodworm) and insulated according to current standards. New windows and shutters will also be installed, but with only double glazing, though with a thermal transmittance value of 1.0 W/(m²K) (0.18 BTU/(ft²·h·°F)).
The exterior walls are 60 cm (24 inches) thick slate masonry, and the facade is in good condition. However, we want to avoid insulating the exterior walls for cost reasons.
Therefore, the planned energy efficiency measures are limited to the roof and windows. Is this sufficient to meet legal requirements? Or is it mandatory to insulate the exterior walls when purchasing an old house?
Maybe someone can also tell me the approximate cost of an energy consultant, or is one not necessarily required? There is no energy performance certificate.
Thanks in advance!
We will start renovating a house built in 1930, which has been in the family. The roof will be completely replaced (there was woodworm) and insulated according to current standards. New windows and shutters will also be installed, but with only double glazing, though with a thermal transmittance value of 1.0 W/(m²K) (0.18 BTU/(ft²·h·°F)).
The exterior walls are 60 cm (24 inches) thick slate masonry, and the facade is in good condition. However, we want to avoid insulating the exterior walls for cost reasons.
Therefore, the planned energy efficiency measures are limited to the roof and windows. Is this sufficient to meet legal requirements? Or is it mandatory to insulate the exterior walls when purchasing an old house?
Maybe someone can also tell me the approximate cost of an energy consultant, or is one not necessarily required? There is no energy performance certificate.
Thanks in advance!
Altbau1930 schrieb:
We have 60cm (24 inches) thick slate exterior walls, Please share some photos of that. How certain is this information? Slate as a structural material for monolithic walls is known to me, but even considering regional differences, it is rather uncommon for buildings from around 1930. The Pellenz and Vulkaneifel regions are full of houses with a thick slate facing layer (or more commonly basalt in this area), but behind that, the walls are usually built with pumice blocks. Along the Moselle River, a similar pattern likely applies, just with different stone materials. At least for buildings dating from 1930.
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A
Altbau193026 May 2017 15:11Thanks again!
The term "slate wall" comes from the current owner, who has lived in this house all her life; her father originally had the house built. Fortunately, the original construction plans from the building period, as well as all renovation and extension plans and repair or replacement invoices from the following years, are still available. A thick stack of papers, but very useful to understand many details. Repairs were always carried out immediately.
Luckily, we already know the house well since, as mentioned, it has been in the family. We can inspect or measure anything at any time, even when craftsmen need access to take measurements for cost estimates.
This is a huge advantage compared to a house usually bought from a third party. There, after one or two viewings, you already need to have a rough idea of the renovation costs, and follow-up expenses due to "surprises" should not be underestimated. If you’re lucky, you have an expert or architect with you, ideally even a surveyor.
Finally, the owner's statement regarding the exterior masonry: ground floor and first floor are slate masonry (according to the 1930 plans, 60cm (24 inches) thick), the floor above, the second floor, is made of pumice stone masonry, 50cm (20 inches) thick.
Regarding the roof:
There are currently two dormers, which will be removed later (in agreement with the building authority / planning permission) and replaced by Velux windows. Dormers are not cheap; for our purposes, we don’t need them anyway (open roof structure).
Otherwise, there are two quite ordinary roof types without much complexity. What I already know: the price difference between interior insulation and exterior rafter insulation is huge, with exterior insulation costing almost twice as much. We still need to consider this: open roof structure = exterior insulation and “nicer” visible timbers inside, or insulation on the inside with the framework covered by drywall.
Fortunately, we have at least half a year for idea gathering and assigning contracts. We also estimate about 4 months for the renovation, even though we will carry out as much as possible ourselves.
However, we will leave the electrical work and the roof entirely to the professionals.
The term "slate wall" comes from the current owner, who has lived in this house all her life; her father originally had the house built. Fortunately, the original construction plans from the building period, as well as all renovation and extension plans and repair or replacement invoices from the following years, are still available. A thick stack of papers, but very useful to understand many details. Repairs were always carried out immediately.
Luckily, we already know the house well since, as mentioned, it has been in the family. We can inspect or measure anything at any time, even when craftsmen need access to take measurements for cost estimates.
This is a huge advantage compared to a house usually bought from a third party. There, after one or two viewings, you already need to have a rough idea of the renovation costs, and follow-up expenses due to "surprises" should not be underestimated. If you’re lucky, you have an expert or architect with you, ideally even a surveyor.
Finally, the owner's statement regarding the exterior masonry: ground floor and first floor are slate masonry (according to the 1930 plans, 60cm (24 inches) thick), the floor above, the second floor, is made of pumice stone masonry, 50cm (20 inches) thick.
Regarding the roof:
There are currently two dormers, which will be removed later (in agreement with the building authority / planning permission) and replaced by Velux windows. Dormers are not cheap; for our purposes, we don’t need them anyway (open roof structure).
Otherwise, there are two quite ordinary roof types without much complexity. What I already know: the price difference between interior insulation and exterior rafter insulation is huge, with exterior insulation costing almost twice as much. We still need to consider this: open roof structure = exterior insulation and “nicer” visible timbers inside, or insulation on the inside with the framework covered by drywall.
Fortunately, we have at least half a year for idea gathering and assigning contracts. We also estimate about 4 months for the renovation, even though we will carry out as much as possible ourselves.
However, we will leave the electrical work and the roof entirely to the professionals.
Altbau1930 schrieb:
Finally, the owner’s statement about the exterior masonry: ground floor and first floor are slate masonry (according to the 1930 building plan, 60cm (24 inches) thick), the floor above, the second floor, is pumice stone masonry, 50cm (20 inches). This cannot be ruled out, but for that construction year it is rather unusual. However, you don’t have to rely on assumptions—there is a lot you can find out: such assumptions can be evaluated with each small hole you drill into the wall. Window reveals can reveal quite a bit, especially considering what was seen during the last window replacement. Thermographic imaging is also a helpful tool for investigation.
Altbau1930 schrieb:
There are currently two dormers that will be removed later (in agreement with the building authority) and replaced by Velux windows. Dormers are not cheap anyway, and we don’t need them for our purpose. You only stand on the “sill” of a roof window when it is open; a vertical window offers a completely different view. That shouldn’t be underestimated. The dormer itself slightly blocks the wind, which is different for a roof window. When it comes to insulation, every roof construction counts as an “obstacle” in the “continuous layer.”
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
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