Penetrating damp not resolved by tanking

[Ciarand]

This is a bit of a long issue to explain, so I will try to keep it succinct 

 

18 months ago a large tree at the top of my front garden was removed and then 6-9 months later we had a water leak from the main rd empty into our front garden for 3 months and was completely flooded/saturated.

 

The garden is 7ft above the floor level of my flat (lower ground floor flat) and has a retaining wall in front of the property. However we have a galley kitchen whose inner wall is against the side end of the garden and most of the wall is below ground/garden level.

 

During the flood into our garden, we started to get what looked like rising damp appear along the full length of the galley wall with some evidence of water coming between some of kitchen floor tiles.

 

We had a damp proof company come advising we needed the wall retanked. So once the leak into the garden was repaired we got the company back to do the tanking. This was completed in July. However we noticed wet patches  starting to appear at the end of the wall and along the wall floor edges  every time there was heavy rain

 

The company came back in November and redid the section at the end of the wall and put some waterproofing material along the floor edge.

 

since then we have not noticed any damp/wet arrears reappear in the edges of the tanking. However the end patch they redid has some small areas of damp which never dry and indeed get bigger when there is heavy rain and also I noticed a few weeks ago small almost tear like drops of damp appear 4ft above the floor level with a few drops below

 

Reason for using this forum is to get advice on the remedy  I have been advised by the damp company to dig a trench in the garden parallel with the kitchen wall = 7ft deep 1ft wide and 10ft long (same length as the galley wall) and fill it with waterproof concrete). They say it is to stop the water going onto the garden being pushed up against and penetrating the kitchen wall

 

Is this a reasonable solution for this damp problem and will it work

 

I will include dome photos to help explain (though not able to include all in one post)

pic 1 this end of the garden sits against the kitchen galley wall - we are in the lower ground flat

pic 2 end of our inner kitchen galley wall

pic 3 shows retaining wall starting after the window iin the galley kitchen

 

All comments /advice most welcome

[nod]

Perhaps they should be doing it 

I presume they have guaranteed there work 

What they are suggesting is pretty stupid If you where to go to the trouble of digging a trench that deep 

It would be cheaper and more e drive to fix a tank inking membrane against the exterior and backfill with pea gravel and add a drain at the same time 

 

Get then back to do the job properly 

[kandgmitchell]

7ft deep and 1 ft wide?? as if that could be dug. This solution isn't just a "remedy" it's a lot of engineering. As a flat you will be leasehold and will need approval from the freeholder/management company for that sort of work. There must be a better solution.

 

Out of interest is that return wall shown in picture 3 abutting your kitchen? Is that the worse location for damp?

 

[Ciarand]

Thanks for your comments and sadly yes it is abutting the kitchen and about 5ft -6ft below the black gas meter container is where the damp is penetrating through as per pic below

[Ciarand]

Thanks for the advice, since the post and responses I have spoken to a few builders and taking all on board.

 

I will wait until dryer/warmer, then will dig out the trench to just below kitchen floor level and put in some waterproof concrete at a slight angle to enable drainage from bottom of trench past the lower part of the retaining wall.

 

For the external kitchen wall, once trench dug allow the bricks/wall to dry out before applying a waterproof membrane. Then place on the bottom of the trench and extending up to close to top of the external wall Pond lining as another added waterproof layer. Fill the drench with small stones with a drain pipe at bottom of trench to ensure effective drainage

Hopefully problem then solved (fingers crossed)

[ETC]

I really think you need professional advice. You should really speak to a civil engineer who specialises in basement construction.