I am renovating a house that I was given by my grandparents. I was pulling up the carpet to get to the wood flooring beneath it and noticed that the carpet was damp. I found a spot in the floor closest to the outside wall that is rotten. Upon further investigation I found that the ground (dirt) is only about a foot from the bottom of the floor. I really don’t want to tear up the whole floor since it is old wood and is in good condition throughout the rest of the room but I really need to fix the moisture problem. The house is built on a steep hill and that is the room closest to the top. The moisture is bad enough I think I am getting mold in the walls(which I know I am going to have tear out and replace after a good cleaning. Can you give me any suggestions on how to fix this? I don’t have a whole lot of money to spend but I can save up for it if something drastic needs done. Thanks!

  • AB Architectural Design Ltd

    Hi Tiffany,

    If the ground level on the back of the room is higher than the floor level internally then you will have to tank the walls of this room either internally or externally depending on your circumstances.
    If however the ground level outside is lower than the internal finished floor level by at least 150mm then it might just be that you need to install a damp proof course (DPC) and this can be injected into the external wall.
    It sounds like you might also have some wrotten floor joists on the ends which means you may need to take up the existing floor boards to replace these anyway.
    I would recommend you get a damp specialist to look at this properly and if the joists are wrotten it might also pay to get a structral engineer to take a look at the floors.

  • Darren Mackenzie

    Do you know if you have a cavity wall or a solid one?
    If the ground level is higher outside the building than the floor level inside, a cheaper option would be to dig a small trench outside and against the existing wall. A trench 100 – 200mm should be sufficient dig the trench at a depth that is slightly deeper that the inside floor level, then fill this trench with pea shingle, the shingle will help with drainage and water sitting against the outside wall.

    Another solution which would cost more but is inline with what AB Architecture is recommending would be to dig a slightly larger trench along the outside wall. This is to give you better access to the outside wall, you then prime the wall with a bitumen primer, ready to accept a bitumen sheet. The bitumen sheet is a waterproof tanking system used to prevent water being absorbed into the wall.

    If you want to go all out you can inject the two courses at the same level as your internal floor level with an injection damp system, before fitting the bitumen system.

    If you would like some ideas of cost you can send me a direct message at Darren@forestoakestimates.co.uk I have just priced a job for someone with same problem so I have the figures to hand and it would cost me nothing to give them to you.
    I hope this helps?

  • Tiffany Robinson

    Thanks both of you for the help, the floor is level with the ground outside. That portion of the house doesn’t have a basement and only half a crawl space. The walls are cavity walls. I’m not sure if they have insulation in them but I know they are pretty much hollow. When my grandfather and uncle built the house the dug out part of the hillside and put in a retaining wall. There is a space about 61 cm wide between the retaining wall and the wall of the house. There is vinyl siding on the house and wood behind it. That part of the house does not have any cement block. Thanks for all the help!

  • Stephen Williams

    If you have mould you have condensation which will cause timber decay. Internal tanking is easier and more reliable look on Sovereign’s website at the Heydi system it works! If your in the Northwest call me for free survey 07812061925.

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