ᐅ Is it possible to effectively insulate the basement floor after construction?
Created on: 11 Dec 2018 12:46
N
netzplan
Hello everyone,
we have already consulted an energy advisor and are waiting for a quote, but we still want to gather some information in advance.
We plan to completely renovate our house. As part of the renovation, the exterior facade will receive continuous insulation. In the initial consultation, the energy advisor recommended insulating the basement ceiling with about 8cm (3 inches) of insulation as well.
During the full renovation, we are considering raising the ceiling height in some basement rooms. The architect said this would require underpinning (by 1 or 2 meters, respectively). On the other hand, a construction manager suggested that it might be possible to simply remove the slab foundation and lower it by about 20-30cm (8-12 inches). However, the final decision lies with the structural engineer.
My question now is: Is it feasible to install insulation underneath the slab foundation if it is removed and lowered as planned, as shown in the sketch? Wouldn’t thermal bridges occur as indicated? Or would the insulation become ineffective due to thermal bridging since the strip footings are not covered by continuous insulation?
Note: In the sketch, the slab foundation has not yet been lowered.
we have already consulted an energy advisor and are waiting for a quote, but we still want to gather some information in advance.
We plan to completely renovate our house. As part of the renovation, the exterior facade will receive continuous insulation. In the initial consultation, the energy advisor recommended insulating the basement ceiling with about 8cm (3 inches) of insulation as well.
During the full renovation, we are considering raising the ceiling height in some basement rooms. The architect said this would require underpinning (by 1 or 2 meters, respectively). On the other hand, a construction manager suggested that it might be possible to simply remove the slab foundation and lower it by about 20-30cm (8-12 inches). However, the final decision lies with the structural engineer.
My question now is: Is it feasible to install insulation underneath the slab foundation if it is removed and lowered as planned, as shown in the sketch? Wouldn’t thermal bridges occur as indicated? Or would the insulation become ineffective due to thermal bridging since the strip footings are not covered by continuous insulation?
Note: In the sketch, the slab foundation has not yet been lowered.
From an energy perspective, I wouldn’t worry too much about the thermal bridge. Any additional measures to reduce it would not be cost-effective.
Insulating the basement floor is actually not straightforward. From below, it’s an energy-efficient solution, but in terms of construction effort and foundations, I would think carefully about it.
Will the basement be used as living space? Daylight? If not, then insulating the basement ceiling is definitely the much simpler solution.
Insulating strip footings from the outside as shown is also not an easy task, structurally speaking.
Insulating the basement floor is actually not straightforward. From below, it’s an energy-efficient solution, but in terms of construction effort and foundations, I would think carefully about it.
Will the basement be used as living space? Daylight? If not, then insulating the basement ceiling is definitely the much simpler solution.
Insulating strip footings from the outside as shown is also not an easy task, structurally speaking.
Thanks for the tips. We plan to use half of the basement rooms for living purposes (guest room, hobby room, etc.). That’s why we’re considering increasing the ceiling height. If we can actually do this (after consulting with the structural engineer), the question would be how to insulate it effectively. In fact, more important than insulation is to think about possible issues with groundwater pressure. So far, there haven’t been any problems here, but you never know what nature might do in 10 to 20 years. Maybe I’m just overthinking it and simply insulating the basement walls (excluding the foundation) will be enough.
(The basement walls are white and sandy in some areas).
(The basement walls are white and sandy in some areas).
I would think carefully about this project.
What is the current ceiling height in the basement?
If the basement rooms are to be approved as living space, are there sufficient window areas?
The whole thing will easily cost around 40,000 (40k), by which time you could also build a small above-ground extension.
What is the current ceiling height in the basement?
If the basement rooms are to be approved as living space, are there sufficient window areas?
The whole thing will easily cost around 40,000 (40k), by which time you could also build a small above-ground extension.
netzplan schrieb:
We plan to use half of the rooms in the basement for living purposes (guest room, hobby room, etc.).netzplan schrieb:
The ceiling height is currently about 2.15 meters (7 feet). An additional 20–30 cm (8–12 inches) would be ideal. Light wells will be installed then.And you and your guests are all over 2 meters (6 feet 7 inches) tall, so you constantly have to walk bent over? If the budget is tight, go ahead with lowering the floor, but guests in the basement guest room will probably use it mainly for sleeping, so ceiling height is likely less important there. And unless your hobby is basketball or skipping rope, 2.15 meters (7 feet) ceiling height shouldn’t be an issue.
Properly waterproof and cover the basement floor from the inside. Achieving a warm basement floor in an existing building is not easy—or rather, getting it warm is possible, but doing so without moisture issues is tricky. There are some discussions about this here. There are several approaches, depending on preferences or “beliefs.”
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