Damp in garage workshop

[Peter Sefton]

It’s good news you and the builder are moving on, you could deal with the floor as I previously mentioned which has worked for us.

Cheers Peter

 

[Dibs-h]

So, the builder came around and admitted there was a problem, saying the concrete and mortar had not had a chance to dry out properly.

He left a dehumidifier with me for 2 weeks, which I ran along with heating (he'd hired the dehumidifier at his own cost). He has also offered to lay a wooden floor over a damp proof membrane, where I pay for materials, and he covers the labour. His plan is to lay the DPM on the existing concrete floor, lay 2x2 joists on that, and then fix ply to those. I'm aware of the issue of breaching the DPM when fixing the joists to the floor from Dusty's response. Can the breaches be sealed, or should the joists not be fixed to the floor?
I was also wondering if it is worth putting insulation under the boards to warm the place up, and I'm planning on boarding up the ceiling as well, potentially with insulation between the rafters. Do you think this makes sense?

Overall I'm happy with the response from the builder, and hopefully the workshop will be a cosier more pleasant place to do stuff at the end of all of this.

Cheers,
Fingerless

FingerLess

I did something similar for my shed. Lay the DPM down (be nice if you could lap it to the DPC in the walls) and you lay 3"x2" down around the perimter and then lay 2"x2" down in between. Making sure things are a tight fit. Almost like making a timber framed wall but dropping it onto the floor. No reason to screw thru the DPM into the floor - so no breaches to deal with. Just "toe screw" the end of the 2"x2" into the 3"x2" (which is laid sideways)

Ply straight onto the 2"x2" - filling the gaps between the 2"x2" 1st. 16" centres should be ok and "noggins" where boards meet the other way.

Assuming your concrete is actually level.

HIH

Dibs

p.s. Obviously my floor has 4"x4" going round the perimeter and 4"x2" across.

 

[RogerBoyle]

Please tell me I have got this wrong

Mr Builder lays a new floor on a new bit of an extension Knowing what it is to be used for and fails to fit a DPM.. His solution is to now lay a DPM on the new floor and raise the level by a minimum of 3 inches and wants you to pay for it I.E. the materials..Has he said who is paying for the electric on the dehumidifer as they can be expensive to run Depending on model

Am I the only one that thinks this is unacceptable

 

[Lons]

Please tell me I have got this wrong

Mr Builder lays a new floor on a new bit of an extension Knowing what it is to be used for and fails to fit a DPM.. His solution is to now lay a DPM on the new floor and raise the level by a minimum of 3 inches and wants you to pay for it I.E. the materials..Has he said who is paying for the electric on the dehumidifer as they can be expensive to run Depending on model

Am I the only one that thinks this is unacceptable

As a builder, I agree with Rogers comments.............. However, getting him to rip up the floor and do it properly is another matter. Unless the construction of the floor was specifically detailed in his quote and/or drawings, which you should have approved prior to awarding the job, you don't have a leg to stand on. Remember that it's not a dwelling which would have been subject to building regs. and inspection.

The builder knows damn well that the problem isn't "hasn't had time to dry out" and the reason for the dehumidifier is to get the surface of the floor as dry as possible before laying a DPM. A waste of time if the damp is coming up through the floor.

His solution will work ok but the labour will be a small part of the cost and he's getting off lightly. Better than nothing if no other way but I wouldn't be happy.

If you're putting in heavy machinery, make sure there's plenty of support in those areas btw and possibly consider some electrics? Insulation well worth it 'cos impossible later.

Bob

 

[Peter Sefton]

Please tell me I have got this wrong

Mr Builder lays a new floor on a new bit of an extension Knowing what it is to be used for and fails to fit a DPM.. His solution is to now lay a DPM on the new floor and raise the level by a minimum of 3 inches and wants you to pay for it I.E. the materials..Has he said who is paying for the electric on the dehumidifer as they can be expensive to run Depending on model

Am I the only one that thinks this is unacceptable

As a builder, I agree with Rogers comments.............. However, getting him to rip up the floor and do it properly is another matter. Unless the construction of the floor was specifically detailed in his quote and/or drawings, which you should have approved prior to awarding the job, you don't have a leg to stand on. Remember that it's not a dwelling which would have been subject to building regs. and inspection.

The builder knows damn well that the problem isn't "hasn't had time to dry out" and the reason for the dehumidifier is to get the surface of the floor as dry as possible before laying a DPM. A waste of time if the damp is coming up through the floor.

His solution will work ok but the labour will be a small part of the cost and he's getting off lightly. Better than nothing if no other way but I wouldn't be happy.

If you're putting in heavy machinery, make sure there's plenty of support in those areas btw and possibly consider some electrics? Insulation well worth it 'cos impossible later.

Bob

I agree, I am not saying the builder is correct just sometimes you have to move forward with a problem and I am not commenting on who should pay.

 

[RogerBoyle]

Sorry guys I thought i was cracking up when i read this as it seemed that nobody was saying the builder was just wrong to do this and now he wants the customer to pay for it to be fixed.

Fingerless

Did you have any plans drawn up for the builder specifiyng the layout and what materials to be used ???
If as Lons has suggested see if they mention a DPM on them either written on the plan or in the notes .
As a matter of interest how big an area are we talking Because if its not to big I really would be pressing him to dig it up and redo it .
Its not that hard a job to do just very noisy and extremley dirty/dusty.

Roger

 

[Lons]

I agree, I am not saying the builder is correct just sometimes you have to move forward with a problem and I am not commenting on who should pay.
_________________
Peter Sefton

That's the way I read your post Peter. Sometimes you just have to bite the bullet and accept or decline the offer. If it were me however I would be pushing a bit harder until that point was reached. A reputable builder would put it right even if it wasn't specified. As a professional, he should have suggested that a DPM was at least desirable if not essential. I would!

Bob

 

[RogerBoyle]

I agree, I am not saying the builder is correct just sometimes you have to move forward with a problem and I am not commenting on who should pay.
_________________
Peter Sefton

That's the way I read your post Peter. Sometimes you just have to bite the bullet and accept or decline the offer. If it were me however I would be pushing a bit harder until that point was reached. A reputable builder would put it right even if it wasn't specified. As a professional, he should have suggested that a DPM was at least desirable if not essential. I would!

Bob

I totally agree 100% with that

Roger

 

[adzeman]

The major problem is that the underside of the ply panels are now covered in mould,

This is a clue, The mould is a type of mushroom who's spores are ever present in the air. They float around looking for the right conditions so they can set their seed.
The conditions are three in number which are:-
1 Darkness. Cant do much about this as we have night time and cupboards etc up against walls.
2.Moisture. Cant do much about this either as we have humidity in the air and condensation.
3.Still Air. This we can do something about. Ventilation (also cures condensation)

Take away any one and you cure mold growth Ventilation is the easiest solution.

One other thing If it catches hold it needs none of the three things as it sends out Micella (fine fibres) and infects any surface.

Oh another thing, it takes three weeks to kill it. Keep applying the treatment till its dead. How do you know its dead? Rub your hand over it and look at your palm. If its black its still alive. If its silver its dead.

 

[adzeman]

Sorry bad spelling again! Mycelia

 

[MARK.B.]

I would reccomend that when dealing with the mould that you wear a suitable respirator as the spores of some moulds can be nasty and you dont want something that likes warm damp places getting into your lungs.

 

[adzeman]

If the mold has caught hold it would be better to bring in the proffessionals as they have some pretty leathal stuff. At the council I had a dediated team of two blokes booted and suited. You coud contact the council and they would do it for a charge. Less than a private company.

If it is of manageble proportions you can buy mold removal from B & Q but I found you can use ordinary household bleach a lot cheaper which comes with free elbow grease to treat every day for three weeks.

 

[adzeman]

Most important, have you a couple of these? Are they clear? best opposite each other.

How about a picture of your mold growth to show extent.

 

[fingerless]

Hi All,
Thanks for the opinions and suggestions. Apologies to Peter, I missed your post about how your floor was done. I think I will follow that advice as it was in line with what I was thinking and has worked for you, and then I need to get the ventilation sorted out.
Cheers,
Fingerless

 

[Peter Sefton]

No problem, I hope it all gets sorted out and you can get on with woodworking.

Cheers Peter

 

[Phil Pascoe]

Mike B. Are your air bricks better opposite each other? I'd have thought the opposite - that anywhere but would be better. I know from keeping aquaria that if the filter inlet and outlet are opposite each other you get "dead" areas where there is no circulation - I'd have thought the same would happen with air?
phil.

 

[adzeman]

No they are not due to it being a terrace of garages and I have the middle one so I have to depend on the drauaght under the up and over door.

As a matter of interest in a previous post in general woodworking I mentioned my own workshop is condensation free and I put this down to when I work in the shop I have my dust exctraction working. This keeps the air moving and stops the dust settling. Well I am making some alterations at present and the some of the tubes altered which means its switched off. I have had 100mmm of snow on the roof, freezing temperatures and an electric heater on and I HAVD CONDENSATION! The snows gone, but its still very cold (as we speak) I am still working in the shop with the heater on and the Vac system sort of running in an incomplete state. No condensation.

 

[pip1954]

hi all as an ex builder i think some are missing the point first what was asked for, you should not have to second guess what the customers want, the other thing people are saying take it up but by the sound of it it is a raft ie under the walls not inside the walls what if there is no dpm under the exsisting garage why would you put it under the new bit ,yes it would be best practice but the place will be damp because of the old part, it will also always be damp because single skin brick.
my answer would be to strike best deal with the builder and bite the bullet i think the way forward would be to think what would be the best out come,
i would dpm then insulate the floor with one of the 8x4 sheets types maybe with ply bonded to it then put 3/4 ply over the floor as discribbed with timber around it and between sheets to leave a very good finish just fix ply to timber not to concrete leave dpm long enough to go up the walls above dpm in walls then if you board walls you can put it behind timber battens for wall boarding
i would think it would be about best of a bad job . if mine i would insulate walls and ceiling and floor that would mean minimal heating in future
ok i'm going to hide now (hammer)
pip

 

[buffalobill]

Maybe this could be an easy solution
http://www.atechtt.com/tech/index.php?o ... &Itemid=53

 

[adzeman]

“I think some are missing the point first what was asked for, you should not have to second guess what the customers want,”

You are quite right in your assessment and without more detailed information one can only give advice as to how you see it or have experience. Also it is always easy to blame the builder. There are cowboy builders out there but not as many as the media like us to believe.

We are only guessing at the construction and remember the Victorians did not use Lead core D.P.C’s, membranes under slabs, insulation, cavity walls.

What do we know?
The roof is 3 layer felt on ply. No mention of insulation.
The ply is covered with mould growth. Cause, lack of ventilation, no mention of insulation?
Windows double glazed. Are they vented? Again possible lack of ventilation.
The walls are brick, Are the H.B. single skin? 1B single skin? Or HB facing on 100 insulated blocks? No mention of air bricks. Relationship of damp course with external ground level, concrete slab or existing garage.
Bad weather conditions are mentioned but the initial set in concrete is within approx 20mins from then on its in curing mode. (if on a rising thermometer)
Therefore, as Pip1954 states how can we help? The only definite cause we know until further info givenis is a lack of ventilation.