Damp in Garden office..

[Oggy76]

Hi All,

I am just after a bit of advice if possible. I have a garden office which was built by a friend as a bit of a favour.

The office is now 2 years old and is made entirely out of wood and sits on a layer of hardcore, sand and large concrete slabs.

I am now seeing quite a bit of damp forming at the bottom of two of the walls by the double glazed door and when I lift the carpet up around the edges of the room I can see damp on the floor by the edges of the door and also in an opposite corner of the room.

Most of the other edges are all dry though?

The office entirely covers the concrete floor and I am not sure if the damp is coming up through the floor or not?

Any advice you can offer would be be greatly appreciated about how I could locate and solve the issue?

Many Thanks in advance.

 

[kbdiy]

Does it sit on any kind of damp proof membrane and how high off the ground is it?

 

[Oggy76]

I don't think a damp proof membrane was put under it. and it sits about an inch or two above ground level.

 

[kbdiy]

That is pretty much what I suspected. If it is only an inch or two off the ground then it will be soaking up water from the surrounding ground. Having carpet inside will not help as that will hold on to the moisture. The damp may be coming from below or could be from rain soaking up the walls. Most likely it will be both.

To stand any chance of preserving the structure it needs to be raised at least 6" off the ground and ideally be supported on a damp-proof membrane of some description. However given that the damp has already penetrated this may not completely eradicate the problem and raising it may be a considerable task (you do not mention the size and type of construction). Also the timber would need to be treated with a preservative if not too far gone.

Eliminate the source and hope for a dry summer, but the damage may already be done.

 

[Chri5]

Does the shed have a guttering system?

 

[Oggy76]

Many thanks for your response kbdiy.

Oh dear it doesn't sound good at all. The office is around 15ft x 10ft with a double glazed door and two double glazed windows so I cant see anyway of raising it to solve the issue?

 

[Oggy76]

Does the shed have a guttering system?

No it doesn't. Here is an image.

 

[Oggy76]

and another image. The damp seems begin at the bottom of the door architrave.

Is there anyway of raising a structure of this size to insert a membrane?

 

[Chri5]

Do you think it's rising damp, or could it be ingress via a weak door seal and the obvious fact that any rain fall will run off the roof and straight down the front and rear due to lack of guttering?

 

[Oggy76]

I have checked again this morning and the damp patches are isolated to all four corners of the room and the door entrance.

If it was rising damp would I see damp patches in the middle of the floor also?

 

[kbdiy]

Unfortuantely it's just general proximity to the ground that is causing your problem and the outer skin is the first to suffer because of that and exposure to driving rain. The fact that you are not seeing any visible damp in the centre is purely because it is further from the source.

As it is such a large structure you are unlikely to be able to lift it to limit any further damage. Without seeing the location etc the only suggestion I can make is complete dismantling to effect a suitable remedy, which is probably not what you want to hear, but as these buildings come at considerable cost it may still be worth considering.