Workshop Flooding

[Jasonb]

Digging a sump at a point where your french drains run and installing a pump with float switch will allow the collected water to gather in the sump where it can then be pumped away.

Jo's suggestion of the main drains goes against what a lot of LAs allow as it causes pollution when heavy rain and runoff overloads the foul water system but it may be possible to pump to another point where the water can flow away naturally and become someone else's problem

The only other option if external access is limited is to form a drained cavity within the existing structure where you allow the water to leak in and then again have a sump where it can gather and be pumped away as needed but that would be a complete strip out of the workshop. This is usually better than an internally applied tanking layer.

[Michael S.]

Hi Mike,
a suggestion for an emergency solution, maybe for a longer time:
There are 1 liter cans with an epoxy resin mixture with glass fiber reinforcement in our hardware store. Offered for the roof, this can be smeared directly onto wet surfaces and will stick to almost any material. This can is not expensive to try.
I google what that stuff is called.

[Michael S.]

Water stop.

https://www.amazon.de/MEM-500503-Water-Stop/dp/B001JAGY3W/ref=asc_df_B001JAGY3W/?tag=googshopde-21&linkCode=df0&hvadid=231889154076&hvpos=&hvnetw=g&hvrand=15803942503433509552&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=20227&hvtargid=pla-486411570877&psc=1&th=1&psc=1

[tghs]

what about adding a drainage well to the drainage system, add a float switch activated sump-pump to get the water to where it will drain away.. that way when the weather is better the wall area will be much less wet to do repairs..

[Vixen]

Thank you all for your well meaning suggestions regarding external drainage.

As I said in the intro post; this is a problem containing many other problems. None of them easy or satisfactory.

Jason has hit the nail on the head regarding many of the problems I face.

Connecting the existing 'French' drains to a common sump with a pump would appear to be a solution. However, why is there always a however? However, that would require a court ruling to compel my uncooperative neighbour to let me dig a 1 metre deep trench in this garden and flower beds to replace the existing 'French' drains and make the sump. Obtaining a court ruling is not guaranteed, as a sharp lawyer could argue that using the building as a machine shop is a significant change of use (and regulations) from it's intended purpose of a garage in which to park a car. Then, where to discharge the pumped water? Local authority regulations don't allow the discharge of heavy rain runoff into the foul water system. I cannot think of a viable alternative.

So you can see I have little alternative than to deal with the water ingress within the garage/ workshop itself. Fortunately, if that's the right choice of words, The flooding only occurs after very heavy rain storms, a few times each winter. For ten months of the year it id relatively dry and there is no problem. When the flooding occurs, it is only for a few days until the saturated ground water level returns to normal.

I like Jason's suggestion about a drainage cavity within the building to collect the water and a sump/ pump to dispose of it. Food for thought.

Steve, I contacted the manufacturer of the 'cement tanking' and obtained their product data sheets and some good advice. Yes the 'tanking' is mostly Portland cement which is impervious to water when set. 'Tanking', as it's name implies is used to line water tanks and swimming pools it can also be used to line cellars, inspection pits, lift shafts etc. The latter applications rely on good adhesion of the 'cement tanking' to the substrates. Adhesion is usually better to brickwork than to concrete flooring. They did not seem surprised that the 'tanking' I applied years ago, has eventually delaminated from the concrete floor. Perhaps due to thermal expansion stress, summer and winter, over the years. They did recommend the addition of  SBR (styrene butadiene copolymer rubber) which is a water resistant adhesive, to the 'tanking' mix. The SBR addition  does two things; it promotes adhesion to difficult surfaces like concrete and secondly it give a slight flexibility to the 'tanking' which would other wise be a hard but brittle shell. It sounds like a useful addition, it must be applied and allowed to dry. I would have to wait until a long spell of dried weather to chip out the existing tanking and replace it with the recommended alternative. Dry weather would also allow me to move stuff outside to allow access to the walls and floor.

So plenty to think about for the future. In the mean time, following several dry days, the ground water level has dropped, drained away,
 sufficiently to stop the water forcing its way in. I can efficiently deal with future flooding with a dry wet vacuum cleaner. I can live with that until the warmer weather arrives.

Michael S. I will try to obtain a tech data sheet for that MEM Water Stop material, it may be another alternative.

Thanks again for all your help and advice

Mike

[RReid]

Considering Crash's previous line of work, he can't be too bright. Perhaps he could be persuaded that the stuff on the floor is spilled beer, but still drinkable. Then it could be legally transferred to the sewer system as pee?

[Vixen]

 

Mike

[vtsteam]

While the materials and use are ridiculous for the purpose here, I sometimes wonder if this principle has any application:

To temporarily fix a wooden boat with a slow leaking seam while afloat, oatmeal was put in a shaker with a handle and released adjacent to the suspected leak. The oatmeal was drawn into the seam and swelled, plugging it from the outside. This was apparently sometimes used as a pre-sale technique for a tired hull.

Similarly in water tanks of reinforced concrete, sometimes lime in the water will plug a crack over time by deposition, in the same way that cave stalactites are formed. I know this is true by personal experience having built an 8 foot tall 3000 gallon fresh water cistern.

I do wonder if a product could be made to fix an external leak by injection outside of the leak, without digging up a foundation wall.

[Vixen]

Similarly in water tanks of reinforced concrete, sometimes lime in the water will plug a crack over time by deposition, in the same way that cave stalactites are formed. I know this is true by personal experience having built an 8 foot tall 3000 gallon fresh water cistern.

Researchers say the reason why Roman concrete structures have proved to be so durable over 2000+ years, is because they added additional lime to an otherwise standard concrete mix. The Roman concrete was self healing, as any small cracks became resealed by the action of water on the lime.

Mike

I have also heard that adding a spoonful or two of mustard to a leaking car radiator was a useful emergency measure to get you back home. I also heard that cracking a hens egg into the radiator would do the same thing, blocking the leak with poached egg. 

[vtsteam]

Not that such a sealant product exists (that I know of) but speaking hypothetically, injection could be made by drilling say a 1" hole through the wall above the crack. Without disturbing a neighbor.

While it might seem absurd to add a hole to a wall one wants to seal, it is far easier to plug a small through hole than a crack on the inside. Hydraulic cement (expanding cement) fills holes well. One can even cement a permanent capped pipe in that way. I also know that from plumbing my cistern.

[vtsteam]

I think Bentonite is used to seal ponds because it expands in the leakage areas.

[Vixen]

Steve,

Tell me more about hydraulic cement.  Now you mention it, I think there is a process to inject silicon ??? or something similar, it drilled holes in brickwork, to stop rising damp. More stuff to look at

Mike

[Don1966]

I have the same problem Mike, water seeps through the wall. I Have a duel wall and water seeps in between them to a point  where the two wall stop which is into my shop. I tried sealing it with flex seal but it continues to seep through. So i installed a sump pump where the water is coming in, but it hasn’t rained enough yet to test it. Ever time it rains I vacuum gallons of water out of it. Lots of luck in stopping yours I know how frustrating it can be.

Regards Don

[Jo]

Jo's suggestion of the main drains goes against what a lot of LAs allow as it causes pollution when heavy rain and runoff overloads the foul water system but it may be possible to pump to another point where the water can flow away naturally and become someone else's problem

If you are a water utility bill payer with a water meter you will know that the Sewerage charge is twice that of the supplied water charge to take account of taking away the rainwater. It would be nice if all the roads also did not drain into the sewers as we would not get so many sewerage spills when the treatment plants can't cope with the volume of water.

If like poor Mike you live on clay then the only way to get rid of water is evaporation, down the mains drains or letting it run onto you neighbour's property - which is what Mike neighbour has clearly done 

Difficult to do anything with it until it is fully dry and warmer then at least a waterproof surface treatment might stick.

Jo

[Jasonb]

We are on a water meter and all our rainwater goes into soakaways. Not even a combined system is allowed We have three of them pebble filled 3m dia concrete rings and 4m deep.

There is a rebate for properties with soakaways. https://www.ofwat.gov.uk/nonhouseholds/surface-water-drainage/reducing-your-surface-water/

Also got several big soakaways for the road gullhes along the cul-de-sac, these are unfilled 4m rings and at least 5m deep. They also have "overflows" so that in times of heavy rain if the soakaways fill up then there is a 9" bore pipe that goes 25m down through the clay into the chalk layer below