Conservatory floor damp?

[chris765]

Hi,

We noticed that a couple of tiles on our conservatory floor had started to lift and the grout too.

I take the tiles up and a generation of ants are making themselves comfortable underneath.
The ants are gone (almost). I can't work out if the tiles raised because of damp and then the ants got in, or if the ants caused the tiles to lift.

I expected it to be a concrete floor but have found bricks and a DPM about 12" away from the external wall.

I'm wondering if those bricks were going to be the external wall but then it got changed?

Thanks.

Is there a way of finding out if there is rising damp, or a damp issue? View media item 61046 View media item 61047 View media item 61048 View media item 61049

 

[dann09]

1. The ants are attracted to the damp conditions - the ants are irrelevant.

2. The membrane obviously stops short - it should lap up the outer walls.

3. The adhesive has never properly adhered (stuck) to the tile or the sub-surface. And the damp areas ( beyond the membrane ) have become the most vulnerable and loose.
Are you happy with the soundness of the remainder of the tile?

4. Can you post some pics of the exterior showing the lower level conservatory connection to the house, and perhaps annotate where the conservatory FFL comes on the outside brickwork - hopefully, it's about 150mm above ground level.

5. Given the oddities so far, perhaps you could (using a spray bottle) carefully water test the conservatory frame and glazing for leaks?

 

[chris765]

Thanks for your reply.
The tiles that have lifted are along the line of bricks that are showing. My bet is that there's no DPM on it.

The DPM on exterior wall is <150mm, this is due to the lady living here before us having the patio raised higher, looking at our neighbours house it would have been >150mm before the patio was built.

I will left the rest of the tiles and remove dot n dab plasterboard to get a better look of what is going on.

We haven't noticed any leaks.
Thanks,
Chris.


View media item 61058 bottom of tape is FFL - about 120mm high.

View media item 61059 House is on the left, conservatory is on the right.

View media item 61060 House is on the right, conservatory is on the left.

 

[dann09]

1. The blue membrane/DPM can be seen peeping thro just before the brickline. Hence all beyond the membrane might be at risk of rising damp.

2. The water test was only suggested for the lower section of the conservatory wallframe - test, and look for moisture appearing on the floor.

3. Depending on how much tile you lift - perhaps the whole field - you will also have to remove the mastic adhesive, and prepare the concrete surface before re-tiling using a powdered adhesive ( "thin-set").
Mastic is for amateurs, or particular circumstances.

4. The first thing is to determine the cause of the damp. The next thing would be to decide what to do about the lack of a DPM and the inappropriate bricks.