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Mass concrete houses....ADVICE

  • 14-07-2014 3:42pm
    Registered Users Posts: 126 ✭✭

    My partner and i are looking at purchasing a 1940's mass concrete detached property. As we are first time buyers, we've no experience with this type of thing. We had an architect out to look at the house who informed us that the house was constructed from mass concrete and dampness will be an issue. However a solution was proposed. Insulating the external walls, preventing further moisture seeping in (like a jacket for the house). However, given that over 70years of moisture is currently lodged in the walls they will need to be dried out. My questions are as follows:
    1. Has anyone first hand experience of mitigating dampness in concrete walls,
    2. How long did it take to dry them out (either naturally or induced)
    3. Did the dampness reoccur following mitigation measures?

    Any advice would be appreciated.


  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 17,280 Mod ✭✭✭✭DOCARCH

    Are the walls damp? Were the walls tested?

    Not sure what type of house it is or where it is but I have dealt with a couple of mass concrete built ex-corporation houses in Dublin and have yet to come across an issue with damp in the walls.

  • Moderators, Home & Garden Moderators Posts: 10,130 Mod ✭✭✭✭BryanF

    Total depends on the house. Assuming you can mitigate rising dampness/ ground water level around the footings

    Did he use the word dampness? Or did he suggest there were signs of condensation?

    Positive input Ventilation and external insulation are the way to go with mass concrete homes

  • Registered Users Posts: 118 ✭✭no1murray

    Knock it down and build a timber frame.

  • Closed Accounts Posts: 4,029 ✭✭✭shedweller

    no1murray wrote: »
    Knock it down and build a timber frame.
    Aaaand what if you pay the going rate for a then add on the price of a whole new timber frame?
    Lotto much?

  • Registered Users Posts: 118 ✭✭no1murray

    shedweller wrote: »
    Aaaand what if you pay the going rate for a then add on the price of a whole new timber frame?
    Lotto much?

    Sorry wasnt being serious. External insulation is the way to go with vents lots of vents. If planning a gut of the house and space isnt at a premium I would go with dry lining and vent into the air gap with vents lots of vents. Did I mention vents.

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  • Moderators, Home & Garden Moderators Posts: 10,130 Mod ✭✭✭✭BryanF

    no1murray wrote: »
    I would go with dry lining and vent into the air gap with vents lots of vents. Did I mention vents.
    tell us more about venting the drylining?

  • Registered Users Posts: 118 ✭✭no1murray

    BryanF wrote: »
    tell us more about venting the drylining?

    Im reverting to my previous position of knock it down and build a timber frame.

  • Registered Users Posts: 27 OBrother

    You don't have enough facts to answer the questions asked.
    Damp is something that penetrates a building.
    Condensation comes from moist air hitting cold surfaces.
    Damp is prevented entering the house by using damp proof courses in the walls, good quality plastering to the external walls and a dry roof. Mass concrete walls are not bad, most council houses built in the 50's and 60's and a lot of the Land Commission houses around Meath and Kildare are built with this and as stated previously show few problems.
    External insulation will be effective for both plaster problems and condensation but will not prevent rising damp or a porous roof problem.
    If the plaster is in good condition you may have another problem.
    If the house is not lived in for some time it could be damp just from lack of heating and ventilation and condensation has built up.
    These walls normally about 250 mm thick will dry out in a few months, in a well heated and ventilated house.

  • Registered Users Posts: 25 dinglebay

    I live in a mass concrete house, built in 1930's. Only problem we've had was with condensation on an outside wall in the breakfastroom which is open to the kitchen.
    Problem only became evident when I lifted a painting off the wall and found black mould behind. Solved by dry lining - no problem since.
    No rising damp. House is, despite the construction, surprisingly easy to heat and keep warm.
    I have come across a situation where a cavity formed by drylining had to be ventilated by vents from the outside, this was where insulated plasterboard had been fixed using plaster dabs, not the best detail.

  • Registered Users Posts: 8 Stollen

    Hi I am a newbie here but I have an interest in this thread. I too have a family member living in a mass concrete house built in 1949. The walls are solid concrete blocks about 10 inches thick with a roughcast render outside and sand and cement and hardwall inside. It suffers from condensation on the single glazed aluminium windows. The fireplaces are blocked. central heating was installed 35 years ago and the living space has poor ventilation. There are timber floor joists and floorboards there is a dpc in the wall so no rising damp. Timbers in floor and roof are bone dry ( plenty of ventilation)
    There is some mould caused by condensation and poor ventilation on the walls in the corners.

    The house needs an upgrade and I believe that the problem is a classic solid wall cold on the outside warm on the inside so you have condensation. Apart from proposed new windows with vents then venting the blocked fireplaces, insulation in the roof and floor and airseals my query out there is the wall insulation.

    The standard external wall insulation method of 100mm with the acrylic render would totally destroy the nice 1940 features and the look of the house. The wall area is approx. 250m2. I don't like the plasterboard and insulation inside it takes the space away and anyway they put 30mm of white polystyrene behind a plasterboard 30 years ago with a plastic sheet. I am dreading looking at the walls when it is stripped!!

    I have a solution an insulated lightweight breathable plaster ( waterproof external ) about 25mm outside to go over the roughcast plaster ( This stuff will stick to glass) and 20mm internally. The cost would be the same as the external render but it will keep the features. The plaster has a U value of 0.09 Wmk or 0.07 Wmk ( cost). The plaster would also allow and moisture in the wall to breathe ( or on the spec sheet vapour diffuse) Has anybody done this type of system. The plaster can be worked for cold bridges on the cills externally and down the wall below the dpc internally. I am not an expert I don't have all the answers but I want to line up my elderly relation before they engage a professional. Any comments please.

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  • Moderators, Home & Garden Moderators Posts: 10,130 Mod ✭✭✭✭BryanF

    Please PM me details of what you are talking about,cheers

  • Registered Users Posts: 1 wfttogo

    Can you give me the details and source of the insulated lightweight breathable plaster. I'm also looking at insulation options for a mass concrete home.

  • Moderators, Regional North West Moderators Posts: 45,325 Mod ✭✭✭✭muffler

    They haven't been logged in for the last 7 years so I don't think you will get a reply. Personally I have never heard of that type of plaster. Snake oil springs to mind.

  • Registered Users Posts: 751 ✭✭✭C. Eastwood

    Surely your Architect had various Moisture Meters and other necessary Surveying instruments when carrying out the Survey of the house for you.

    Taking moisture readings of the skirting boards would confirm if rising ground dampness is present.

    Checking the moisture in the walls above the skirting boards and taking moisture readings in the concrete walls from the skirting board to the ceiling, in many locations, would also give necessary details of either rising dampness and or ingress of rainwater. Etc

    All Construction Professionals are obliged to have these Surveying instruments and be trained in the use of same for carrying out such Building Surveys.

    This house is over 80 years old. Probably the wrong orientation. All the rooms will be the incorrect location and size. Windows are probably all very small. Etc etc.

    It will be very expensive to modernise to your needs and requirements and the Building Regulations etc. You will still end up with a 1940 designed house.

    My advice is the same as no1murray above - demolish the house and construct a new Timberframe house.

    With this programme, you can have your bespoke house and, you can get the exact costs to demolish and rebuild, etc before commencement.

  • Registered Users Posts: 762 ✭✭✭keno-daytrader

    You are responding to a post that's 8 years old. 😏