Newly Built "wet" garage

[markie0mark0]

Hi Everyone, wondering if some of you can give me some advice on a few problems im having with a newly built garage.

I recently just built a sectional concrete garage, with a large concrete base, up and over door and metal roofing sheets.

The construction is complete now, but im having some big problems with damp and wetness.

list of a few problems:

1. condenstaion is a real big problem, i currently dont have anything inside the garage and just have a couple of "dry" heaters to keep the temp from reaching low figures, i also have a dehumidfier in the garage to try and suck the damp from the air. Im currently in the process of insulation the metal roof to try and get a barrier between the contrasting temps, but not finished yet.

2. is damp through the floor and the concrete walls. The floor has been down for 6 months + damp proof membraine layed before the rebar and concrete went down, im pretty sure this is working as for the majority of the floor (i.e. the centre of the garage) it is dry. The problem i am getting is the walls looks soaking wet, unless the heaters are directly infront of them, also 2' around the edges of the garage on the inside the floors are damp, i put a fillet of concrete and damp proof mix around 1-2 months ago, but it still seems wet. the panels have been sealed each panel to the next but not on the floor.... I also watersealed the walls but unfortunatly a few hours later it rained so im pretty sure this didnt work.

So in short, im hoping the insulation on the roof solves the condensation, but im stumped on the wet walls, they are a fair few years old. But how am i best sealing them again?

thanks all
Mark

 

[JohnD]

where is the condensation forming?

Don't understand these bits...

I recently just built a sectional concrete garage...

...the wet walls, they are a fair few years old.

how long has the roof been keeping the rain off?

Is rain falling on the slab, on the outside of the wall?

 

[markie0mark0]

where is the condensation forming?

Don't understand these bits...

I recently just built a sectional concrete garage...

...the wet walls, they are a fair few years old.

how long has the roof been keeping the rain off?

Is rain falling on the slab, on the outside of the wall?

Hi John,

Condensation is/was forming on the metal roof and then running down the roof to the walls, but with the heaters and the dehumidier, this has stopped and it is just to a level of "slight mist" on the metal roof, not running anywhere, so with the insulation, heating and odd running of dehumidier this should stop, im hoping!

The roof was finalised around 2months ago, its watertight and not leaking anywhere.

And yes, rain is hitting the walls and then running down onto the fillets on the outside of the base, these are around 1-2 months old also, plastisizer (sp) was mixed in with the concrete when mixing the fillet mix. i've also sealed these with waterseal.

The only place there the base is flat is at the front and i plan to grind a angle to chanel the rain away, this will be painted with bitumen paint.

cheers mark

 

[Tipper]

Is there any permanent ventilation? ie end to end or side to side so as to promote a cross flow of air.

BTW dehumidifiers don't do much when the temperature is low and heating the inside in this weather will only promote condensation.

I'd be inclined to ensure it's well ventilated and leave it unheated to dry out naturally.

 

[markie0mark0]

Is there any permanent ventilation? ie end to end or side to side so as to promote a cross flow of air.

BTW dehumidifiers don't do much when the temperature is low and heating the inside in this weather will only promote condensation.

I'd be inclined to ensure it's well ventilated and leave it unheated to dry out naturally.

Hi tipper, ventilation is in the form of a 18" inch vent with a extractor fan on the inside, blowing outwards.

I've also left the up and over door open for a few weeks to vent the garage and it only went worse not better.

The heaters are dry heat, so no flames etc to promote humidity. With the dehumidifier running it pulls around a liter of water a day from the garage.

I want to try and steer clear of lots of ventilation due to security for the garage.

 

[noseall]

Guys, guys, guys, this aint about condensation so much as it's piddling it down and the garage is getting wet from rain.

A concrete sectional garage is not a premium product and they are historically...er...wet.

By nature of their construction the toe of the slab attracts external moisture making them very difficult to seal.

You will spend £££'s keeping out the wet when what you should have done is spent £££'s building a conventional strip foundation masonry structure.

 

[markie0mark0]

Guys, guys, guys, this aint about condensation so much as it's piddling it down and the garage is getting wet from rain.

A concrete sectional garage is not a premium product and they are historically...er...wet.

By nature of their construction the toe of the slab attracts external moisture making them very difficult to seal.

You will spend £££'s keeping out the wet when what you should have done is spent £££'s building a conventional strip foundation masonry structure.

Hi Noseall,
im afraid you lost me on two counts, toe slab? do you mean the base of the garage on the outside of the wall?

"conventional strip foundation masonry structure" not sure what this is either, im no builder, but the garage is built on a budget. My previous sectional concrete garage never had these problems either.

So im at, where im at, so solutions to my problems is what i need, i cant afford to rip the garage down and start with a new method

Also just for reference, the base is at least 8" higher than the surrounding area, specifically built up to prevent any water problems.

thanks mark

 

[noseall]

If the garage slab is bigger than the walls then this creates a 'toe' on which the rain can gather and cause problems.

I have lost count of the posts complaining of this very problem regards concrete sectional garages.

Whilst your efforts to raise the slab 8" are noble, they are in vain.

A large soffit on the roof overhang may improve things.

 

[markie0mark0]

If the garage slab is bigger than the walls then this creates a 'toe' on which the rain can gather and cause problems.

I have lost count of the posts complaining of this very problem regards concrete sectional garages.

Whilst your efforts to raise the slab 8" are noble, they are in vain.

A large soffit on the roof overhang may improve things.

Ah ok, yes the toe out has a fillet directing the rain away from the walls, as mentioned above.

The roof already has soffets and guttering fitted.

The only rain is from the droplets landing on the walls