damp under wooden floorboards

[penfold74]

Hi
We have been living in an old (1896 I think) small semi for years no problem. Now (last 4 weeks) as we enter the font door we can smell damp. We have 2 air bricks on the front wall and 2 on the side wall. The house is effectively a 2up/2down. The damp seems to be coming from the front room(floor boards over earth with a gap). I have just moved a cardboard box that has been there a few weeks and its mouldy. We have never had this before.
The room at the back is above a cellar - with a well in the floor. A pump & float switch regulates the emptying very well.I am wondering if for some reason the ventilation isn't sufficient in the front air space and I should knock a few brick out between the cellar and the front floor space to increase the ventilation.

The only things that have changed is I re-varnished the floorboards in the front room last year.
There was talk years ago that the water in the cellar comes from a burst pipe in the pavement but the council/Anglian water investigated by putting dye down the road drains (I know it wont show a burst pipe but that is all they would do after arguing about who was responsible for weeks for the pavement). They put a camera down the villages main surface drain pipe next to our house and relined it -yet the water was never stopped filling up the 'well'. (They are planning on building 400 new houses yet we will only have this one drain to keep from flooding - is it just me or does that not make sense?)
Questions:
Q - who do I ask professional advise from?
Q- Do I get my insurance involved?
Q-After clearing out the vents do I knock out a couple of brick between the cellar and front floor space? how long do I wait to see it this works
Q- Do I have to lift up the lovely floorboards (please say no)
Q- the floorboards in the front room corner only have always been (20 yrs I've lived here) a centimetre from the skirting - do I have a bigger problem.
Q- is it a damp company issue for a general builder

Many thanks

PEn

Many thanks

 

[pinenot]

You might just have provided the answer in the varnishing of the floor boards. As I was reading your post I was wondering what had changed and was going to reply with that as a question, so I'd best explain my thinking.
By introducing a moisture impervious barrier this may (may) be stopping movement of internal atmospheric moisture, which at floor level is probably the coldest air in the house, cold and trapped moisture = condensation.
Are the floorboards covered or open? ...pinenot

 

[KenGMac]

Hi.

I tend to agree with pinenot, the only significant vapour barrier appears to be the varnish?

As for pulling in so called "Professional damp proofing SPECIALISTS" I have reservations, there are some Cow boys out there.

having said that one firm, nationwide cover, is Polygon, this firm offer a specialised survey of the water that is entering your home.

They can [as a cost] tell you as to whether the water contains any of the following, Faecal material [Indicates that there is a leaking Sewer] the presence of "Soap and Detergent" [indicates the possibility that a "drain" is leaking] or simply ground water.

Bottom line with the results is that if Detergent / Soap / faecal content is located in the water entering your home the Local water undertaker is DIRECTLY responsible, where else can this contaminated water be coming from apart from a leaky sewer or similar?

You can contact the firm and get quotes for their services, it MAY prove a leaking public underground Sewer or similar?

Ken

 

[pinenot]

Assuming I am correct, the placement of a small dehumidifier in the vicinity would resolve the problem...pinenot

 

[KenGMac]

pinenot,hi.

My thoughts were that if a Sump pump has been fitted and is working to remove water getting into the Solumn then there is an "outside chance" that there is a leaky drain / Sewer "somewhere?"

If so then a chemical analysis of the water will either prove or disprove this and if proven the Questioner can present proof to the Local Council and Water provider that there is a leaky drain / Sewer in the vicinity?

Given that the original question notes that the smell of dampness has worsened in the last 4 weeks could indicate that the leak [if it exists] in a publicly owned drain / Sewer has begun to increase, given we have had a fairly "dry" Summer and not too much rain lately relatively speaking.

What to you think?

Ken

 

[pinenot]

If a sewer were leaking and causing you dampness under the floor boards, I'm quite sure the smell would be pervasive, enough for you to know it...pinenot

 

[KenGMac]

hi.

Not necessarily, I have had claims [I work in Insurance, claims as a Surveyor] where there was ingress of water, somewhat intermittent.

No smell at all because all but the microscopic bits of Faecal had been "filtered" by the ground between the break and the Property.

 

[jockscott]

Check that the airbricks haven't been blocked with leaves/detritus etc. Whilst refurbishing a house a few years ago, the front airbricks had been blocked with leaves, allowing water to build up underneath the floor, (house was on a slope) A few weeks of rain had allowed the water to build up to the bottom of the floor boards.

 

[penfold74]

Hi

Thanks for all the suggestions.
To answer a few points the floor boards are the old fashioned straight type ie not t&G and not covered ie no carpet etc. I varnished a year ago could it have taken this long to show up?

The airbricks are free from debri.

If I took a sample of the water and tried to get it analysed (to see if it has come from a burst pipe) any suggestions who I would send it to (apart from the one mentioned - I live in Northants)

Tonight i'm going to knock out a few bricks between the cellar and front air gap - i'll keep you informed of my findings. Really hope there is no obvious water sitting there
Cheers

 

[AronSearle]

2 air bricks at the front and 2 at the side does not sound adequate, you normally want through air flow (if you have them at the front and side, what happens in the furthest corner?), and that's for "normal" houses with suspended floors, if you have cellars or wells, you want more ventilation than normal, you've been lucky.


The varnish would have reduced air leakage into the house, which may help provide additional ventilation, but that's fine, you want the underfloor area to be properly ventilated, not through your living space.

It's also possible your will get increased internal condensation on the walls and floors, as you now have less internal ventilation, and likely cold walls in a house of that age. If this is the case you can fix this by either adding more ventilation (extraction fan, open windows, or re-creating a leaky floor), or if you want to do it properly, more insulation, between the joists and insulation backed plasterboard (assuming no cavity), some, but much less ventilation will be needed.


Q - who do I ask professional advise from?

Property care association

Q- Do I get my insurance involved?

Is anything damaged?

Q-After clearing out the vents do I knock out a couple of brick between the cellar and front floor space? how long do I wait to see it this works

Humidity readings will tell you if it works, a proper surveyor should be able to handle all this.

Q- Do I have to lift up the lovely floorboards (please say no)

Ideally yes, to put some insulation in there (it's the year 2013, not 1913 anymore), but anyway. You will want to check the ends of the joists to ensure they have not decayed or are wet, it's possible you can drill some discreet holes through the floor if you can locate them, and take moisture readings, before deciding if this is necessary. You can probably avoid it, depends on how thorough you want to be.

Q- the floorboards in the front room corner only have always been (20 yrs I've lived here) a centimetre from the skirting - do I have a bigger problem.

?

 

[pinenot]

Just to pick up on somethings i.e. -

the floorboards in the front room corner only have always been (20 yrs I've lived here) a centimeters from the skirting - do I have a bigger problem.

This gap from below will be adding more ventilation into the room thereby any modification would exasperate the problem and not answer it, but ideally it should be closed in this day and age to lessen heat loss. That said the original problem still has to be investigated and resolved first, any upgrades could be done alongside any reinstatement works.
I know the OP wants to leave as much of the original flooring undisturbed so with familiarity with older builds I would ask if any access to the solum/under boards is available? ...pinenot

 

[penfold74]

Hi
So I took out two bricks in the wall between the cellar and front room air gap (about 3foot gap between floor & floorboards)- not an easy job and it looks dry. Not knowing how high the front was compared to the cellar I took out bricks high up & cant get to touch the ground but no smell of damp or visible wetness, but cool in temp. Now what? There is no visual damp ie black mould, up the walls in the front, although I know I did have a little behind the bookshelves when I redecorated last year.

My house is drafty anyway - sash windows and wooden doors, no plastic double glazing here, but some secondary in places.

Could the damp be coming from the big window in the room- no sign of it, but the suspected damp is in the corner 12" from the window? Although it smells worse near the front door (next to the front room and the other side of the wall the said dodgy corner)

Is it time i get a surveyor in?

Cheers for all your help

 

[AronSearle]

Hmm

Damp happening behind bookcases or behind objects could be condensation, the problem with a house of that age is that it will have extremely bad insulation, so even with lot's of ventilation, you will still get condensation where air flow is restricted, like corners or behind things, simply because surfaces are so cold.

The varnish acts as a vapor barrier (so condensation will occur on it's surface if the floor is uninsulated), as well as the varnish getting between the gaps of the floor and sealing it up (reducing ventilation to the floor and adjacent walls).

If it was me I would get a moisture meter (£80), pull up a few floorboards, and check the moisture contents of the timbers below (joists), if all seems OK, then I would think it safe to assume it's a condensation issue and not any kind of rising damp (usually no such thing) or lack of ventilation in the sub floor (on paper what you had was insufficient, but probably not if it's lasted so long).

Assuming that's the case, then one of the following should fix it.

1. Get used to the cold, increase ventilation, move bookcases away from external walls.

2. Get a dehumidifier, you will need to run it high to decrease the humidity to fairly low levels to stop condensation on excessively cold surfaces, you will still likely get condensation in corners that have furniture in them.

3. Run the heating excessively high to drive out moisture.

4. Insulate the floor (pull up the boards, insulation between joists), insulate the walls (insulated plasterboard), this will greatly reduce condensation, but ventilation will still be required, and you still want to be wary of keeping corners clear as you won't be adding that much insulation).

The latter is the most work, but will save you lot's of money over time, and will increase your comfort.

 

[pinenot]

As you can gain access via a cellar, I would advise you have the access portals knocked through to the whole Solum, this would allow both full inspection and corrective works.
Like A .S.I'm inclined to agree that what your describing is condensation, the varnishing has created a vapor barrier allowing moisture in the air to condensate on any area not receiving good ventilation. As suggested a dehumidifier run to reduce the moisture content would be a good idea, as/and would be a ceiling fan (with bookcase etc. off the wall) to provide a movement of static air.
For future care humidistat extractor fans in the kitchen and bathroom would keep the moisture levels down thereby managing the problem...Phew all this just because you wanted some nice varnished floors...pinenot

P.S. If you do insulate under the floorboard, make sure there is sufficient ventilation down there.

 

[penfold74]

Hi
Update. The smell has gone. I'm not sure why - it went before I got the dehumidifier. I removed the bricks (no smell from air gap). I also borrowed a dehumidifier - I got 125ml of water for 8 hours use the first day, then used every other day and got about 5-8ml for 2 hours use. I don't think this is excessive -am I right

I never did get condensation on the windows so cant judge that.

I think i'll leave the bricks out in the cellar to increase ventilation- I wont bother putting in vent bricks because it is in the cellar i'm not worried about the look of it -am I right?

I did notice that under the skirting boards and the floor boards along the front of the house someone has squashed in foam (proper stuff like you get in old cushions) into the 3mm gap.Some is missing a cold air is coming through from the air gap. My partner said to fill it in with caulk or similar to help warm the room better (radiator is on full), but i'm not sure because it will just put us back to the ventilation problem. Should I just put foam back in - at least that stops some breeze but allows ventilation. I even think cut up cork tiles may have been used in some places - old remedies for an old problem! What do you guys think I should do - i'm prone to leave alone and be cold- but that's because i'm getting out of my depth
thanks for all your help so far