Hi all,

Long story but we are living in a tide house (i.e. comes with my wife's job as a curate) for about 18 more months. The garage is an old marly concrete one and the end of the garden.

Snag is the garage was damp, so as part of taking the position we had roof replaced, as the roof had gone porous. This was done, and during the summer all was o.k.

Now it's cold and wet the damp has returned at the door end and far end around about 1m in at each end (better than it was). And stuff is going moldy, including the new roof (and hopefully not the MK's leather seats!).

I think the damp is mainly rising damp and possibly runing in a the door end.

The concrete floor is cracked due to nearby tree roots and this is in the area where the floor is wet. (I guess the damp proof membrane is also cracked).

One problem is that the replacement roof does not allow for ventilation (the old was open at the ends), so once it is damp it will not dry out..

My initial thoughts are:

1) Cover floor in rubber floor from bigdug (~£66) to stop rising damp, by acting as a vapour barrier.

2) put a batton under the mat near the door to stop water coming in that way.

3) get a de-humidifier that works on a humid-stat.

I can then take the floor mat and de-humidifier way for the next place.

What do you think? Good idea? Or is there something else I should do?

Dan

Some photos of the problem:

Door end:


Door end damp 1


Door end damp 2

Side damp (not a lot):


Side damp

End damp (furthest from door):


Far end damp

Mold on roof:


Mold on roof


[Edited on 31/1/10 by Bluemoon]

[Edited on 31/1/10 by Bluemoon]

[Edited on 31/1/10 by Bluemoon]

Can we see some pictures ?

The pattern and colour of the dampness tells a great deal about the source and possibly the cure too.

Short video carefully shot to avoid showing all your valuables would be even more helpfull.

would say if things are going moldy its due to lack of ventillation, if you are ok with dry but cold then would add some vents back, also if its stale damp air i would watch the leather as just looken in my track day fiesta first time in a month and the stering wheel was covered in mold

quote:

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Originally posted by will121
would say if things are going moldy its due to lack of ventillation, if you are ok with dry but cold then would add some vents back, also if its stale damp air i would watch the leather as just looken in my track day fiesta first time in a month and the stering wheel was covered in mold

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quote:

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Originally posted by zilspeed
Can we see some pictures ?

The pattern and colour of the dampness tells a great deal about the source and possibly the cure too.

Short video carefully shot to avoid showing all your valuables would be even more helpfull.

---

looking a photos, is it general water ingress at base/door, these sectional garages generally just bolt to slab with a basic cement fillet, whats the ground level like outside does water sit up against base? would then say this small water ingress is then making the garage damp combined with limited ventillation leading to mold

I'd try force drying the floor then painting it with some nice gloopy concrete paint. It could just be the floor has gone porous and the water soaking into it is evaporating resulting in high humidity.

Worth a try at £20 a tin....

quote:

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Originally posted by will121
looking a photos, is it general water ingress at base/door, these sectional garages generally just bolt to slab with a basic cement fillet, whats the ground level like outside does water sit up against base? would then say this small water ingress is then making the garage damp combined with limited ventillation leading to mold

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It certainly appears going by your descripton and pics that there is more than one issue here.
Clearly, the high ground level will be an issue, but you have addressed that as much as is practicable by digging out and backfilling with gravel wherever possible. Not much you can do about the bits where that isn't possible.
The mould on the underside of the roof deck does appear to be resulting from moist air condensing with the resultant mould formation. Some insulation in this area would ever so slightly raise the surface temeprature, but the mositure will just go somewhere else.
If keeping the car dry is the issue, ventilating the space and possibly trapping the excess moisture would seem like a worthwhile idea.
Perhaps worthwhile investigating passive dehumidifiers.
If you are able to increase ventilation, this can often have a huge impact.

quote:

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Originally posted by zilspeed
It certainly appears going by your descripton and pics that there is more than one issue here.
Clearly, the high ground level will be an issue, but you have addressed that as much as is practicable by digging out and backfilling with gravel wherever possible. Not much you can do about the bits where that isn't possible.
The mould on the underside of the roof deck does appear to be resulting from moist air condensing with the resultant mould formation. Some insulation in this area would ever so slightly raise the surface temeprature, but the mositure will just go somewhere else.
If keeping the car dry is the issue, ventilating the space and possibly trapping the excess moisture would seem like a worthwhile idea.
Perhaps worthwhile investigating passive dehumidifiers.
If you are able to increase ventilation, this can often have a huge impact.

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quote:

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Originally posted by Bluemoon

quote:

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Originally posted by zilspeed
It certainly appears going by your descripton and pics that there is more than one issue here.
Clearly, the high ground level will be an issue, but you have addressed that as much as is practicable by digging out and backfilling with gravel wherever possible. Not much you can do about the bits where that isn't possible.
The mould on the underside of the roof deck does appear to be resulting from moist air condensing with the resultant mould formation. Some insulation in this area would ever so slightly raise the surface temeprature, but the mositure will just go somewhere else.
If keeping the car dry is the issue, ventilating the space and possibly trapping the excess moisture would seem like a worthwhile idea.
Perhaps worthwhile investigating passive dehumidifiers.
If you are able to increase ventilation, this can often have a huge impact.

---

How much "passive" ventilation area is needed?

I have couple of options.

1) Drill/chissel holes in the concreate walls (don't like this as risk of cracking the walls).

2) replace glass windows with marine ply+Vents (there are only 4).

3) Vents in door (probably not good for security).

4) Fit a solar fan (we don't currently have permanent mains, although I could probably rig something up).

5) Try and modify the sides of the roof to add ventilation (difficult as felted around the edges over lapping with the concrete walls).

Any thoughts?

Thanks

Dan

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quote:

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Originally posted by zilspeed

quote:

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Originally posted by Bluemoon

quote:

---

Originally posted by zilspeed
It certainly appears going by your descripton and pics that there is more than one issue here.
Clearly, the high ground level will be an issue, but you have addressed that as much as is practicable by digging out and backfilling with gravel wherever possible. Not much you can do about the bits where that isn't possible.
The mould on the underside of the roof deck does appear to be resulting from moist air condensing with the resultant mould formation. Some insulation in this area would ever so slightly raise the surface temeprature, but the mositure will just go somewhere else.
If keeping the car dry is the issue, ventilating the space and possibly trapping the excess moisture would seem like a worthwhile idea.
Perhaps worthwhile investigating passive dehumidifiers.
If you are able to increase ventilation, this can often have a huge impact.

---

How much "passive" ventilation area is needed?

I have couple of options.

1) Drill/chissel holes in the concreate walls (don't like this as risk of cracking the walls).

2) replace glass windows with marine ply+Vents (there are only 4).

3) Vents in door (probably not good for security).

4) Fit a solar fan (we don't currently have permanent mains, although I could probably rig something up).

5) Try and modify the sides of the roof to add ventilation (difficult as felted around the edges over lapping with the concrete walls).

Any thoughts?

Thanks

Dan

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Dan

If you think that anything which encourages the place to ventilate is a good thing you're off to a good start.
If you have 4 windows arranged 2 per side, then venting one on each side would be good, certainly better than 2 on one side. Encouraging a flow of air throughout the place is what you want to do. Think of how well vented a carport is compared to a garage. That maybe sounds silly, but it's exactly the same principle.
If the windows are 2 a side, I would go for venting one on each side. As you rightly say, anything else is much less practical a solution.

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ventillation at the roof would be ideal but sounds not practicable, by the look of the fit of the door would think there is plenty of potential air movement through there, may me idea to start with some small high/low grills in each corner of back wall, dont need massive grills

Dan,

I'm guessing that the roof is basically wooden and bolted on to the concrete sides? Can you not use longer bolts and then put some timber filler pieces in the resulting gap (with some new vents installed even if this is as simple as drilling through with a 1" wood fleam?).

Doesn't have to be pretty and probably wouldn't take too long?...

HTH

if you really want to waterproof it, you could try vandex rapid S not cheap but has never failed me. I use it when converting basements.

its just a 25kg bag of powder that you mix with water to a slurry consistancy and paint on to walls and floors and the joint between the two.

i would also look at the ventilation too.

What are the walls like for damp?
- If there are porous then sloping some weatherproofing sealant liquid on the outside of them might be a good shout. Same can go on the floor too.

This is what we have used on our garage.
http://www.screwfix.com/prods/52043/Sealants-Adhesives/Sealants/Building-Sealants/Thompsons-Waterseal?cm_mmc=GoogleBase-_-Datafeed-_-Sealants%20and%20 Adhesives-_-Thompsons%20Waterseal

Then i would say ventilation.

Dehumidifier can work but ventilation is better in my book.



Daniel

We have a similar problem here in Canada were it snows alot, car sits out all day at work then gets parked in a warm gargage, snow melts and forms pools of water on the floor. In the last two years we have put a humidifier in the garage which has a sensor and comes on automaticaly, keeps the garage dry and the cars happy.

I think that before going down the ventilation route, you should stop the water from getting in. One thing that you could do is form a cement fillet all around the bottom of the panels, as it would seem that this is where the main amount of water is getting in. Give the area a good scrubbing out, and clean away all and any rubbish that has accumulated in the gaps before trowling in a nice strong sand and cement mix, 3 and 1 (ish), with some water proofed mixed in. Once that has had time to set, then look to try and sort the ventilation. HTH Ray

Thanks for the ideas, as the garage is very full increasing the ventilation the easiest ways I can think of probably simplest to fix first.

The walls are surprisingly dry, it appears that only the base is wet.

I don't care if it's cold in there dry is the first thing.

Lifting the roof might just work, the only problem is it's very heavy (lots of 2x4", and 12mm board), only held on by gravity, no bolts.

My current plan is to monitor the Humidity (I have a remote wireless loging one so I can monitor if I am making progress, whilst in the warm house!). I will set that up tonight.

So my plan is:

1) Replace 4 windows with ploycab ones with the largest vents I can find (the putty on the old windows is falling out and a pane is bust aready).

2) Add vents above the garage door (this as a sheltered over hang from the roof this is the only place I can put the in the roof without lots more trouble).

3) Monitor the RH to see what happens.

I might still cover the floor in a rubber Matt (and this will stop the concrete dust when it's dry, and make it nicer to work in). Having painted 2 garage floors in the last 3 years (when full of stuff) I don't relish the though of doing this again! This might reduce the amount of water vapor in the garage as less damp surface will be exposed, i intend to make the rubber mat a little bigger than required so it kicks up around thew wall.

Chippy, a cement fillet might also be a option latter (there was one all around the base, but is is now breaking up in most places, but where it is good there is still damp), might combine this with putting my floor matt down (as I will have to move every thing in there). Thing is a I have tried to stop the dampness getting in the on side with my trench/drainage and this has not stoped it.

May also look at "vandex rapid S" or similar sealent if the ventilation fails, instead of the rubber flooring depends on cost. If I go this route it will need to stick to a damp surface (it needs to be fixed now not in the summer).

Cheers

Dan

[Edited on 1/2/10 by Bluemoon]