After a water damage (rainwater from outside entering through ventilation), I have renovated my entire basement in my split-level house. A construction company experienced in moisture damage did the work. The house was built in 1976 and the entire basement has an uninsulated slab.
All floors were ripped up; they previously consisted of a framed floor directly on the base slab with foam insulation. The walls were insulated from the inside with studs directly against Lecablock and then fiberglass and foam insulation, finishing with drywall. The only areas that didn't have insulated walls were the shower room and a storage room (other facilities include a laundry room, sauna, shower, and some storage in the basement).
From the outside the walls are only tarred against moisture.
Air supply vents are in all spaces (4 of them) except in the laundry room where it was removed and only exhaust remains, now with a Pax fan, likewise in the shower, there is a humidity-controlled Pax fan.
No old damage was found on any construction in the basement except for some discolorations on the studs around the sauna and shower area, which according to the carpenter was probably due to a leaking floor drain. It didn't smell bad when we opened the floors.
The reason for this post is that I am a little worried about the future and how the renovation was done after reading most posts here on the forum.
All walls that were insulated before were covered with a blue Platon mat against the Lecablocks and then studs were nailed to this, creating a small air gap between the Lecablocks and the Platon mat and stud.
Then fiberglass insulation and drywall were put in place. All baseboards and ceiling moldings were mounted with a small spacer so that according to the carpenters, air exchange could occur in the walls. In both the shower, sauna, and laundry room, they laid a Platon mat on the concrete slab, then foam insulation, and poured on this, with floor heating only in the shower area.
In other rooms, a Nivell floor was installed and all walls were cut and placed on spacers against the slab. However, we never installed any exhaust fan, only spacers for baseboards and ceiling moldings to achieve some form of natural draft? All insulation in the form of fiberglass in the floor is now "hanging" about 10 cm from the concrete slab in the Nivell floor and not, as before, directly against the slab.
I will also be installing a dehumidifier as a preventive measure in the coming days. Before the renovation, it never smelled like a "basement" in the part below ground, maybe a little in one of the storage rooms which has uninsulated walls in the form of an angle outwards. All spaces are heated to about 18 degrees.
I would be very grateful if someone with some knowledge in the area could comment on what they think about the renovation. Could it be possible to insulate the inside of the wall since it seemed to work before and an air gap has been created between walls and insulation with airing via baseboards and ceiling moldings?
Personally, I am most skeptical about the ventilation in the rooms where the floors are poured directly on the Platon mat and do not have a Nivell floor. Could there be some form of ventilation under the Platon mat between ceiling molding and other spaces?
Should all outdoor air vents through the walls in the basement part be closed and use a dehumidifier instead at the expense of ventilation?
Currently, a Pax fan runs continuously in the laundry room, but as mentioned, I intend to install a dehumidifier there instead and only run the fan on a timer for a few hours a day.
Many thoughts... grateful for answers!
Anders
All floors were ripped up; they previously consisted of a framed floor directly on the base slab with foam insulation. The walls were insulated from the inside with studs directly against Lecablock and then fiberglass and foam insulation, finishing with drywall. The only areas that didn't have insulated walls were the shower room and a storage room (other facilities include a laundry room, sauna, shower, and some storage in the basement).
From the outside the walls are only tarred against moisture.
Air supply vents are in all spaces (4 of them) except in the laundry room where it was removed and only exhaust remains, now with a Pax fan, likewise in the shower, there is a humidity-controlled Pax fan.
No old damage was found on any construction in the basement except for some discolorations on the studs around the sauna and shower area, which according to the carpenter was probably due to a leaking floor drain. It didn't smell bad when we opened the floors.
The reason for this post is that I am a little worried about the future and how the renovation was done after reading most posts here on the forum.
All walls that were insulated before were covered with a blue Platon mat against the Lecablocks and then studs were nailed to this, creating a small air gap between the Lecablocks and the Platon mat and stud.
Then fiberglass insulation and drywall were put in place. All baseboards and ceiling moldings were mounted with a small spacer so that according to the carpenters, air exchange could occur in the walls. In both the shower, sauna, and laundry room, they laid a Platon mat on the concrete slab, then foam insulation, and poured on this, with floor heating only in the shower area.
In other rooms, a Nivell floor was installed and all walls were cut and placed on spacers against the slab. However, we never installed any exhaust fan, only spacers for baseboards and ceiling moldings to achieve some form of natural draft? All insulation in the form of fiberglass in the floor is now "hanging" about 10 cm from the concrete slab in the Nivell floor and not, as before, directly against the slab.
I will also be installing a dehumidifier as a preventive measure in the coming days. Before the renovation, it never smelled like a "basement" in the part below ground, maybe a little in one of the storage rooms which has uninsulated walls in the form of an angle outwards. All spaces are heated to about 18 degrees.
I would be very grateful if someone with some knowledge in the area could comment on what they think about the renovation. Could it be possible to insulate the inside of the wall since it seemed to work before and an air gap has been created between walls and insulation with airing via baseboards and ceiling moldings?
Personally, I am most skeptical about the ventilation in the rooms where the floors are poured directly on the Platon mat and do not have a Nivell floor. Could there be some form of ventilation under the Platon mat between ceiling molding and other spaces?
Should all outdoor air vents through the walls in the basement part be closed and use a dehumidifier instead at the expense of ventilation?
Currently, a Pax fan runs continuously in the laundry room, but as mentioned, I intend to install a dehumidifier there instead and only run the fan on a timer for a few hours a day.
Many thoughts... grateful for answers!
Anders
Difficult situation with old basements, as usual......
Obviously, it has worked before (?) and it should NOT be worse now with Platon + Nivell flooring, so it seems fine. However, today I would never have installed wooden studs + insulated the wall on the inside below ground level - that's not good..... Metal studs and no insulation/plastic of the part of the wall that is below ground level is needed. I would also make sure to dig up and insulate with Pordrän/Isodrän on the outside as soon as possible!
Obviously, it has worked before (?) and it should NOT be worse now with Platon + Nivell flooring, so it seems fine. However, today I would never have installed wooden studs + insulated the wall on the inside below ground level - that's not good..... Metal studs and no insulation/plastic of the part of the wall that is below ground level is needed. I would also make sure to dig up and insulate with Pordrän/Isodrän on the outside as soon as possible!