ᐅ Basement Renovation in an Older Home: Do It Yourself or Hire a Professional?
Created on: 6 Oct 2021 15:02
P
piepen55Hello everyone,
I just registered to gather some experiences and opinions regarding the following situation. Briefly about the conditions: We are renovating an old building (built around 1930), which is being converted from a two-family house into a single-family house and upgraded to an energy-efficient house standard 70 or 55. Currently, we are working with architects and an energy consultant to finalize the scope of the construction measures. This means that until we obtain the building permit (also called planning permission), we want to focus on the basement. Based on any feedback we receive here, we hope to better assess whether this is a good idea.
About the basement: It consists of three rooms with a total area of about 56 m² (600 sq ft), which previously housed a workshop (with heating system), a storage room, and a "sanitary area" (bathtub, shower, toilet). Two rooms have window wells, while the third room’s window well was bricked up because a conservatory was built above it. The last-mentioned room (which I call the wine cellar, as we had to dispose of a lot of wine there) was the storage room. This room’s walls were constructed as follows: brick wall → plaster → polystyrene insulation → wood paneling (tongue and groove boards). So far, we have removed everything except the plaster, as the boards were extensively moldy. Since the plaster also shows efflorescence, it will be removed soon. The wine cellar floor currently has particle boards screwed down (previously covered with PVC flooring), and there is a vapor barrier visible underneath the particle boards. The particle boards are also damp. What is beneath the vapor barrier, I don’t yet know.
The other two rooms have tiled walls. Here, the grout, especially along the exterior walls, is at least partially blackened (the closer to the floor, the darker it gets). We will also remove everything down to the foundation walls in the coming weeks. Once we have completely gutted the basement, the question is how to proceed. The planned future uses for the basement are:
The expert advised installing a horizontal damp-proof course just above the basement floor and another barrier near ground level, as water rises through capillary action. With some handyman skills and good tools (both of which we have), it could be done ourselves. The costs would be manageable in this case, whereas hiring a specialized company would likely run into the mid five-figure range. However, his conclusion was that despite all efforts, the rooms could never be made completely dry.
The specialist from the renovation company, on the other hand (understandably from his perspective), recommended against attempting this ourselves, stating that the market solutions for installing a horizontal barrier typically last only 5 to 10 years. He also advised injecting and sealing a similar "barrier material" vertically into the entire affected walls. Furthermore, he said moisture had almost reached the ground floor, the mold was highly dangerous, and cracks could also develop. Whether this was partly alarmist, I cannot judge. We are currently awaiting the company’s offer for the recommended measures. Both the independent expert and the specialist agreed that the rooms are more "wet" than just "damp." The specialist’s conclusion was that the rooms can be dried enough to allow for building a “children’s room” inside.
A third option suggested by our architect is to proceed with the gutting to the foundation walls as planned, make the window wells more air-permeable, and then observe how the moisture conditions develop.
Given the intended use, we certainly do not require completely dry rooms. However, we are naturally concerned about moisture spreading to the upper floors. Installing a horizontal damp-proof course sounds plausible to me, especially since we cannot access the walls from the outside anyway.
My questions to those who have read this far (thanks for that!) are:
Best regards!
I just registered to gather some experiences and opinions regarding the following situation. Briefly about the conditions: We are renovating an old building (built around 1930), which is being converted from a two-family house into a single-family house and upgraded to an energy-efficient house standard 70 or 55. Currently, we are working with architects and an energy consultant to finalize the scope of the construction measures. This means that until we obtain the building permit (also called planning permission), we want to focus on the basement. Based on any feedback we receive here, we hope to better assess whether this is a good idea.
About the basement: It consists of three rooms with a total area of about 56 m² (600 sq ft), which previously housed a workshop (with heating system), a storage room, and a "sanitary area" (bathtub, shower, toilet). Two rooms have window wells, while the third room’s window well was bricked up because a conservatory was built above it. The last-mentioned room (which I call the wine cellar, as we had to dispose of a lot of wine there) was the storage room. This room’s walls were constructed as follows: brick wall → plaster → polystyrene insulation → wood paneling (tongue and groove boards). So far, we have removed everything except the plaster, as the boards were extensively moldy. Since the plaster also shows efflorescence, it will be removed soon. The wine cellar floor currently has particle boards screwed down (previously covered with PVC flooring), and there is a vapor barrier visible underneath the particle boards. The particle boards are also damp. What is beneath the vapor barrier, I don’t yet know.
The other two rooms have tiled walls. Here, the grout, especially along the exterior walls, is at least partially blackened (the closer to the floor, the darker it gets). We will also remove everything down to the foundation walls in the coming weeks. Once we have completely gutted the basement, the question is how to proceed. The planned future uses for the basement are:
- Housing the heating system
- Laundry
- Tool storage/workshop
- Storing food and beverages, including space for a freezer
The expert advised installing a horizontal damp-proof course just above the basement floor and another barrier near ground level, as water rises through capillary action. With some handyman skills and good tools (both of which we have), it could be done ourselves. The costs would be manageable in this case, whereas hiring a specialized company would likely run into the mid five-figure range. However, his conclusion was that despite all efforts, the rooms could never be made completely dry.
The specialist from the renovation company, on the other hand (understandably from his perspective), recommended against attempting this ourselves, stating that the market solutions for installing a horizontal barrier typically last only 5 to 10 years. He also advised injecting and sealing a similar "barrier material" vertically into the entire affected walls. Furthermore, he said moisture had almost reached the ground floor, the mold was highly dangerous, and cracks could also develop. Whether this was partly alarmist, I cannot judge. We are currently awaiting the company’s offer for the recommended measures. Both the independent expert and the specialist agreed that the rooms are more "wet" than just "damp." The specialist’s conclusion was that the rooms can be dried enough to allow for building a “children’s room” inside.
A third option suggested by our architect is to proceed with the gutting to the foundation walls as planned, make the window wells more air-permeable, and then observe how the moisture conditions develop.
Given the intended use, we certainly do not require completely dry rooms. However, we are naturally concerned about moisture spreading to the upper floors. Installing a horizontal damp-proof course sounds plausible to me, especially since we cannot access the walls from the outside anyway.
My questions to those who have read this far (thanks for that!) are:
- Should we install the horizontal barrier ourselves, or
- hire a company to do it as they propose, or
- gut the basement first and wait to see, or
- are there other ideas?
Best regards!
I would completely gut and clear everything except for the foundation wall, even removing the plaster. Then observe the moisture levels under different conditions. Does the wall get damp when it rains? Is the water coming from below or from outside? What moisture readings are there on different days? Are the levels constant or do they change?
In the meantime, you can use the space for laundry.
I don’t understand your concern. If moisture hasn’t risen for the past 90 years, it probably won’t in the next 90 years either. Or is there mold, plaster cracks, or anything else on the ground floor?
If nothing else happens and the space is only going to be used as a storage or laundry room, then that’s manageable.
In the meantime, you can use the space for laundry.
I don’t understand your concern. If moisture hasn’t risen for the past 90 years, it probably won’t in the next 90 years either. Or is there mold, plaster cracks, or anything else on the ground floor?
If nothing else happens and the space is only going to be used as a storage or laundry room, then that’s manageable.
The complete gutting, including removing the plaster, will definitely be done. This will also provide a better view of the foundations, allowing for an inspection to determine if a damp-proof course was ever installed. Additionally, the analyses you mentioned can then be carried out.
So far, we have not found any mold or cracks in the plaster, etc., on the ground floor. In two spots on the ground floor, some of the floorboards are locally rotted or decayed. I suspect the cause is more likely from above rather than from below (the basement).
In the meantime, we have also received a quote that unfortunately would completely exceed our budget.
So far, we have not found any mold or cracks in the plaster, etc., on the ground floor. In two spots on the ground floor, some of the floorboards are locally rotted or decayed. I suspect the cause is more likely from above rather than from below (the basement).
In the meantime, we have also received a quote that unfortunately would completely exceed our budget.
Sure, gut. The entire interior will be stripped down.
There is definitely no damp-proof course installed.
If you cannot access the walls from the outside (why not?), you won’t be able to dry out the basement.
The mold problems are certainly due to the really poorly done interior renovations by the previous owner.
Styrofoam traps moisture, so mold growth is inevitable.
So, remove all of that, apply new plaster, and then leave it as is. It will remain somewhat damp but will dry out with proper ventilation (only when the outside temperature is lower than in the basement). For the intended use, I would skip the effort of installing any additional damp-proofing measures later on, as they usually only last a few years. Structurally, the moisture is irrelevant. The house has stood for 90 years and will stand for another 90.
It’s also a good idea to monitor the condition during the construction phase while it’s still a shell. Depending on the moisture level, you can then decide on the appropriate plaster.
There is definitely no damp-proof course installed.
If you cannot access the walls from the outside (why not?), you won’t be able to dry out the basement.
The mold problems are certainly due to the really poorly done interior renovations by the previous owner.
Styrofoam traps moisture, so mold growth is inevitable.
So, remove all of that, apply new plaster, and then leave it as is. It will remain somewhat damp but will dry out with proper ventilation (only when the outside temperature is lower than in the basement). For the intended use, I would skip the effort of installing any additional damp-proofing measures later on, as they usually only last a few years. Structurally, the moisture is irrelevant. The house has stood for 90 years and will stand for another 90.
It’s also a good idea to monitor the condition during the construction phase while it’s still a shell. Depending on the moisture level, you can then decide on the appropriate plaster.
First of all, thank you for your answers! The "wine cellar" is not accessible because one wall is also the party wall with the neighboring house (it is an end terrace house), two walls border other basement rooms, and a conservatory was later added above one wall. The other two rooms would each be accessible from one wall. According to the experts, however, excavation at these walls from the outside would be disproportionately expensive and complicated.
Absolutely right, the completely wrong interior finishing of the rooms was the major mistake. However, I initially didn’t want to apply new plaster during the construction phase but wanted to observe first. Plaster can still be applied later if we actually need the rooms.
I also think it would be important to check where the rainwater from the gutters is being directed. I wouldn’t be surprised if it’s just draining directly near the house or if the gutters/downspouts are completely clogged.
Would using dehumidifiers help (a frequently mentioned, well-meaning tip)? They would probably collect quite a bit of water, but basically, it would keep running in, and you would basically have to run them all the time? That wouldn’t really help, right?
Absolutely right, the completely wrong interior finishing of the rooms was the major mistake. However, I initially didn’t want to apply new plaster during the construction phase but wanted to observe first. Plaster can still be applied later if we actually need the rooms.
I also think it would be important to check where the rainwater from the gutters is being directed. I wouldn’t be surprised if it’s just draining directly near the house or if the gutters/downspouts are completely clogged.
Would using dehumidifiers help (a frequently mentioned, well-meaning tip)? They would probably collect quite a bit of water, but basically, it would keep running in, and you would basically have to run them all the time? That wouldn’t really help, right?
Similar topics