Hello, we recently became homeowners of a two-family house built in 1966, with 17.5 cm (7 inches) calcium silicate brickwork and 150 sqm (1,615 sq ft) of living space.
Currently, the heating is provided by a central oil heating system with small stoves.
The plan is to install a new heating system with radiators (oil condensing boiler) and then insulate the house, including the roof and basement. The windows are already new.
Initially, 14 cm (5.5 inches) insulation with a thermal conductivity of 0.35 W/mK was planned, but due to difficulties related to the roof overhang and other structural conditions, I was advised to use 12 cm (4.7 inches) insulation with 0.32 W/mK instead.
The interior rooms are all covered with drywall panels and behind that, 8 cm (3 inches) of polystyrene insulation (on walls and ceilings). I am not sure if there is a vapor barrier or an air gap behind, but the walls will have to be opened anyway during the heating system work. According to the seller, this was already done during the construction phase.
Now my questions:
Does external insulation still make sense in this case?
If yes, is the proposed insulation adequate?
How much energy savings can be expected from external insulation?
Currently, the heating is provided by a central oil heating system with small stoves.
The plan is to install a new heating system with radiators (oil condensing boiler) and then insulate the house, including the roof and basement. The windows are already new.
Initially, 14 cm (5.5 inches) insulation with a thermal conductivity of 0.35 W/mK was planned, but due to difficulties related to the roof overhang and other structural conditions, I was advised to use 12 cm (4.7 inches) insulation with 0.32 W/mK instead.
The interior rooms are all covered with drywall panels and behind that, 8 cm (3 inches) of polystyrene insulation (on walls and ceilings). I am not sure if there is a vapor barrier or an air gap behind, but the walls will have to be opened anyway during the heating system work. According to the seller, this was already done during the construction phase.
Now my questions:
Does external insulation still make sense in this case?
If yes, is the proposed insulation adequate?
How much energy savings can be expected from external insulation?
Hello blurboy,
the house was built in 1966, and I assume this was not known at the time.
Not only are the exterior walls insulated from the inside, but the entire room (except the floor) is insulated as shown in chapter 3, image 5 in the link.
Am I correct in understanding that because of this internal insulation, external insulation is not very effective or that only one of the two should be used, with external insulation being the better option?
Regards, Klaus
the house was built in 1966, and I assume this was not known at the time.
Not only are the exterior walls insulated from the inside, but the entire room (except the floor) is insulated as shown in chapter 3, image 5 in the link.
Am I correct in understanding that because of this internal insulation, external insulation is not very effective or that only one of the two should be used, with external insulation being the better option?
Regards, Klaus
Hello,
The previous owner did not apply additional insulation afterwards without reason. A professional advisor could have explained to you in time that this is technically a no-go, before signing the purchase contract. (Intentional deception? Hidden defect?)
Now it can easily become a money pit.
That is probably the case.
Best regards
Klweber schrieb:
...the house was built in ’66 and I assume that back then this was not yet known.
The previous owner did not apply additional insulation afterwards without reason. A professional advisor could have explained to you in time that this is technically a no-go, before signing the purchase contract. (Intentional deception? Hidden defect?)
Now it can easily become a money pit.
Klweber schrieb:
...Do I understand correctly that because of this internal insulation, external insulation is not that suitable or only one of the two should be used, with external insulation being the better choice?
That is probably the case.
Best regards
Hello Euro,
So far, no money has been transferred, and the previous owner (an estate community) is still clearing out.
An expert inspected the house and did not see any issues with the interior insulation, even though I had mentioned exterior insulation.
Best regards, Klaus
So far, no money has been transferred, and the previous owner (an estate community) is still clearing out.
An expert inspected the house and did not see any issues with the interior insulation, even though I had mentioned exterior insulation.
Best regards, Klaus
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