Damp under decking

[ajacklin]

Hi, we’ve just purchased and moved into a new property, it has some raised decking the entire width of the rear of the property. We need to jet wash and treat it in spring but I was concerned about the damp course and if the decking could be causing problems before I spend money on maintenance of it. It’s all enclosed, as per the photos, there’s a door for access which was used for storage or dumping rubbish by the looks of it. Is the black paint from the top of the decking some sort of sealant?
There was damp on the internal walls but none reported on the back wall, this was the front walls and the side (semi detached side) I think that was caused by leaking gutters front and rear and I have repaired those.

 

[ajacklin]

 

[JohnD]

The solid wall and door prevent ventilation from drying it. Open it up at two ends or more so there is a through draught. You can use louvres to keep out larger animals, or just open it up.

Look for any gutters or drains delivering water to the decking area and correct them.

Remove the rubbish.

Water will tend to run along the grooves in the boards, if they have any fall on them, so remove any dirt or woodwork that prevents it running off and draining away from your cavity.

 

[foxhole]

Agree with JohnD, those timber supports would be better sat above the ground level ( on brick etc) to prevent rot.
Is there a gap between house and decking.?

 

[Burnerman]

It looks an ideal home for rats.....Id open it up as much as possible.
John

 

[ajacklin]

Thanks guys for the replies, the supports are on bricks, there's some rubbish (a Santa) in the way on the pic. I've pulled most of the rubbish out now. The decking does go right up to the house, i cant decide if to reduce the size of it, up to the left hand side of the steps now and then replace all the sides with trellis or to get rid completely and have a PVC balcony - as you can see theres doors opening from the lounge so it needs something there! Suppose the cheapest option is to leave as is but again replace sides with trellis