Strange smell in house

Discussion in 'Builders' Talk' started by Shaun Reid, Sep 13, 2020.

  1. Shaun Reid

    Shaun Reid New Member

    Hi Guys,

    I posted about this on the plumbers talk awhile back with some really great ideas and suggestions coming back but still having issues in this dam house.

    Here goes:

    My wife and I bought our house about 5 years ago and from day 1 we noticed a strange musty smell. We thought that maybe after we moved our stuff in and lived in it for a bit that maybe the smell would go but no. What’s most annoying is that whatever it is, the smell sticks to everything. Since we moved in, we’ve done the following:

    - replaced all the internal plumbing for new
    - more airflow added to the lines
    - run brand new external sewage pipes to the septic tank
    - added vents in the external line
    - septic tank emptied once a year
    - checked and cleaned the gutters and down pipes
    - changed all the carpets
    - fitted air vents to the soffits
    - checked all down pipes for leakages with all being good

    Outside of our front door, there is an air vent which really does not smell nice. Like I mentioned, it’s like a musty, stale air smell and we are convinced that this smell is what we get sticking to our clothes but just can not find where it is coming from.

    The area has a lot of clay roundabout but not sure if this cause. WRT to the soakaway, the drain specialist who run new pipe work has said that the septic tank is working.

    The house was built in 1970z

    Thanks in advance for any advise.

    Kind regards,
  2. Ian1980

    Ian1980 Member

    With you mentioning the vent near the front door it sounds like ventilation for a crawl space under your floor. Crawl spaces can often be damp and even have standing water all of which will smell musty. If your ground floor is floor board i would be looking underneath. Even if you have solid floors it is possible that a broken grid, gully or soil pipe could be leaking and finding its way under the slab.

    Another cause of musty smells can be a failing damp course
  3. Ian1980

    Ian1980 Member

    Cement renders do not breathe efficiently enough, they trap water in the wall, the waterproofer will hold it back for a while but not forever. Cement render gets overwhelmed and contaminated with hygroscopic salts which becomes a compounding issue of damp permeating through from behind the render and the salts drawing moisture from the air.

    Bridging the built in or injected dpc with render is also on a countdown to failure and even worse is when it is bridged with gypsum plaster.

    Movement/settlement can cause cracks which compromise the waterproofing.

    Inferior waterproofer chemicals dont offer proper longevity

    Dpcs built into the wall were originally bitumin tar which does not resist movement and cracks causing bridging. The upgrade was bitumin felt which does resist movement better but still deteriorates with age and allows bridging. This is not an issue with modern plastic dpc. Slate was also used but does not form a perfect continuous barrier and thus allows bridging.

    Dpcs can also be compromised by improper ground levels against the exterior of walls. This often happens when landscaping works are carried out and ive even seen raised flower beds built against the wall.

    Some cavity wall insulation also holds moisture and also bridges built in dpcs.

    Injected dpcs, either high pressure into the brick or cream in the morter joints, rarely create a continuous barrier and as such a just slowing the dampness rather than eliminating it . This is hidden for a while by cenent renders but as i explained before it wont hold it back forever.
  4. Ian1980

    Ian1980 Member

    The above was a reply to joe the plumber asking how can a dpc fail. The post seems to have since disappeared

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