Author Topic: Water table under the house  (Read 5282 times)

fd3

Water table under the house
« on: June 09, 2018, 10:21:43 am »
At the back of the house there is about 25 cm under the floorboards to the clay soil.  Around Christmas my wife took up the wet carpet and found that the solid was wet, with a bit of a puddle on top.  This was localised in the corner by the neighbours so we suspected some issue from there.

With some diy investigations and dye tests it looks like it is not coming from pipes and might actually not be coming from the neighbours.  I dug further to try and increase the amount of water that would be easily accessible (I thought there might be a puddle next door slowly sleeping into our soil, so a bigger hole would contain more water and I could bail it all out faster).  I found that I was bailing more water, but the level never goes higher than the soil...

I suspect its ground water, but there have been days where the water stops rising, and it does seem to rise at some times faster than others.

Fundamentally though I think that drying out the clay under the house is a bad move, so I’m wondering whether I shouldn’t just check air bricks/ventilation, fill the holes, and as long as the water doesn’t rise above the ground leave it alone.

Otherwise, what should I consider to lower the water table?
Or does this sound like definately not a water table issue.
And we know the flag of love is from above/And we can force you to be free

andytheflyer

  • Andytheex-flyer.....
Re: Water table under the house
« Reply #1 on: June 09, 2018, 03:07:59 pm »
Hi,  I'm a recently-retired engineering geologist, with 40 years experience in assessing groundwater and ground issues as they relate to structures (amongst other things relating to ground and structures)

Firstly, it could be groundwater, and if it is, don't try to lower it by much, otherwise you'll dry the clay and it may shrink a bit.  That's not good news for houses founded on clay.

If you were measuring the true gw surface in a clay, it would not be going up and down noticeably in a few days - it would probably take weeks because of the low permeability of the clay.  Indeed, it would be unusual to see much gw level variation in a clay - sands and gravels, maybe.  Clay, a bit unlikely, unless there's some significant gw removal going on locally - and you'd know about that.

Much more likely is water accumulation on top of the clay as a result of flow over the top of the clay, so maybe runoff from the garden, or next door through the topsoil around your house.  Given that you see relatively rapid rises and falls of water in your holes, I'd strongly suspect flow across the top of the clay, and similarly drainage away across the top of the clay.

I'd have a look at why this has become a problem.  What's changed to give you a problem?   If you can identify that, maybe that provides a solution.  Has next door built a patio so that rainwater now runs off onto your property?  Or do they drain their patio to a drain that's become blocked?  Or a garage roof to a drain that no longer works, so the runoff runs across the ground surface (usually unseen through the topsoil) onto your property?.  If that is the cause, it's up to them to fix it - there's well-known legal precedence here - Rylands v Fletcher).  https://en.wikipedia.org/wiki/Rylands_v_Fletcher

Failing that, arrange some drainage to the top of the clay so that the water can find it's way to your garden and a surface water drain.  You can do a lot with some gravel, wrapped in a geotextile - the fabric sold in garden centres as weed suppressant (looks like a rough woven textile - usually black).  If you can dig a shallow trench in the clay where water accumulates, and lead that trench away to a low spot outside the house footprint  Line the trench with the textile, and fill it with gravel.  Wrap the textile over the top and cover with gravel.  The textile lets water through from the clay to the gravel, but stops fines going with the water flow and evetually clogging the gravel. 

I appreciate that the trench solution may be difficult to execute, but either stopping the water getting under your house in the first place, or controlling the level under your house is the way to go.

If you can identify water flowing over the top of the clay towards your house, you can use the trench as a cutoff, along the ouside perimeter of your house, to intercept the flow and lead it away to a suitable point. 

The identification of potential gw problems in construction, and their solution, comprised a major part of my working life, in those parts of the world where it rains. Less of a problem in the arid world. Whatever, don't try to change the gw conditions by much, otherwise you'll end up with other problems relating to changing the balance of nature. 

HTH, but maybe PM me if you need more.

Andy


Re: Water table under the house
« Reply #2 on: June 10, 2018, 02:44:42 am »
Chiming inform the architect's point of view (not quite retired yet) -

Do whatever you can to isolate the moisture from the interior of your house.  The floor boards and floor framing want to be dry.  If not, eventually, in addition to the wet carpet issue, eventually you'll walk over on that part of the floor and step through the rotted wood. 

25 cm isn't much space to work with.  Is there a way to access the under-floor space and excavate enough soil to get perhaps 50 cm space?  Just enough that you can wiggle through?  Any provision for ventilation of the under-floor area, so the water can get out to the greater atmosphere, and not condense under your floor?  That 50 cm space would give you enough space (wiggling, again) to lay a thin plastic sheet on the "floor" of this crawl/wiggle space, to lessen the evaporation potential.

Having the crawl space would make it possible to install insulation on the underside of the floor (against as-dry-as-feasible wood) to improve comfort inside, as well.

Aunt Maud

  • Le Flâneur.
Re: Water table under the house
« Reply #3 on: June 10, 2018, 09:08:38 pm »
From the building conservationists' point of view, it sounds like you need to do more investigation as you have a potentially serious problem.

There shouldn't be any water in there at all.

fd3

Re: Water table under the house
« Reply #4 on: June 12, 2018, 02:49:13 pm »
Thanks for that.  This leaves me with questions -
andy, the water level (in the hole I dug) is currently staying a few cm below ground level, I am tempted to simply refill the hole and see whether we see the level rise above the clay again.  The neighbours had an issue with the pipes when we moved in, which meant that water was running to this spot under our house - they have fixed that, but I wonder whether there is a natural channel for water to run through that has been formed.  They had a leaky pipe which they also replaced, I wonder how much water will have been stored in the ground and how long it would have taken to sep out - might that explain some of the flow?  Did I mention their ground level is about a foot higher than on our side?
Since the soil is clay and holds some moisture, if I dig a hole in it I will get water flowing to the free space.  Am I being overly hopeful in thinking that if I simply refill the hole and don't see the water rising above ground level I can just ignore it?
Moleman, yes, our old house had about 3' below the floorboards.  We will be getting another airbrick or two for when we put the floorboards back down.  It looks like the wood is dry and the damp guy we had in says that there isn't an issue.
I really appreciate the time you have all taken and your feedback, we have had nearly a dozen different people in to have a look, we have had suggestions from concreting the floor to lowering the path outside by 30cm, but most have shrugged with confusion and either never gotten back to us or point blank admitted that they wouldn't take the job on as they didn't reckon they could fix it.
And we know the flag of love is from above/And we can force you to be free

Aunt Maud

  • Le Flâneur.
Re: Water table under the house
« Reply #5 on: June 12, 2018, 05:19:11 pm »
Why don't you go and dig a hole in your garden and see if it fills with with water ?

Re: Water table under the house
« Reply #6 on: June 12, 2018, 05:27:09 pm »
Your local council or water board may be prepared to test the water and decide its origin. They did for me to find it was spring water due to a rising water table.
A neighbour lower down the road with a similar problem had the water tested and it was found to be caused by the blockage of a conduit on a new build site nearby that the builder had to clear and repair..
Never knowingly under caffeinated

fd3

Re: Water table under the house
« Reply #7 on: June 12, 2018, 05:44:16 pm »
Cheers nobby!  Yes, got the water tested, it's not chlorinated, which suggests run-off or rainwater.

I thought about digging in the path out back (more of an issue if it rains of course), hadn't thought of digging in the garden... would have to see how far down it is to the clay, but also the neighbours are higher next to the house but level once you get to the outbuildings, so would expect to see something different anyway.
And we know the flag of love is from above/And we can force you to be free

Aunt Maud

  • Le Flâneur.
Re: Water table under the house
« Reply #8 on: June 12, 2018, 05:49:20 pm »
It's always good to have a dig around, you never know what you'll find out.

andytheflyer

  • Andytheex-flyer.....
Re: Water table under the house
« Reply #9 on: June 12, 2018, 07:10:02 pm »
Thanks for that.  This leaves me with questions -
andy, the water level (in the hole I dug) is currently staying a few cm below ground level, I am tempted to simply refill the hole and see whether we see the level rise above the clay again.  The neighbours had an issue with the pipes when we moved in, which meant that water was running to this spot under our house - they have fixed that, but I wonder whether there is a natural channel for water to run through that has been formed.  They had a leaky pipe which they also replaced, I wonder how much water will have been stored in the ground and how long it would have taken to sep out - might that explain some of the flow?  Did I mention their ground level is about a foot higher than on our side?
Since the soil is clay and holds some moisture, if I dig a hole in it I will get water flowing to the free space.  Am I being overly hopeful in thinking that if I simply refill the hole and don't see the water rising above ground level I can just ignore it?
Moleman, yes, our old house had about 3' below the floorboards.  We will be getting another airbrick or two for when we put the floorboards back down.  It looks like the wood is dry and the damp guy we had in says that there isn't an issue.
I really appreciate the time you have all taken and your feedback, we have had nearly a dozen different people in to have a look, we have had suggestions from concreting the floor to lowering the path outside by 30cm, but most have shrugged with confusion and either never gotten back to us or point blank admitted that they wouldn't take the job on as they didn't reckon they could fix it.

It's a bit difficult to be definitive as to solutions without seeing the site. T'was ever thus with ground problems.  However, I'll offer advice on the basis of what I can understand from what you tell me.

You've dug a small hole in the soil below your floorboards, it's got water in it but that level has not changed for a few days.  That may not be surprising. It could be the groundwater level (gwl) and so the hole is registering a real condition.  But, since evaporation in that location is likely to be very low, it could simply represent water that has flowed over the top of the clay and accumulated in the hole, but there has been no further recharge, and it's simply sitting there.  If you baled it out and watched the level for a few days, it may or may not refill. That doesn't tell you much unfortunately.  If you have a low-permeability clay stratum, (e.g. London Clay, Oxford Clay, Kimmeridge Clay, and a few others!) it could take gw very many days to refill the hole.  But you may have some weathering in the clay, and hence some higher permeability zones, and that could speed up recharge or, alternatively, the hole refills quickly from surface runoff.

I think it's maybe a key fact that the neighbours have had piping problems and that their land is higher than yours.  Historically-leaked water could well be stored on their land, and it's making its way onto yours by flowing downhill.  Water can be stored in the topsoil and near-surface soils and is released from storage slowly, so even if they've cured their (known) leaks, you may see flow for some time to come.  How long is it since they cured their known problems?  They may have further problems that they don't yet know about too.

I'd just keep an eye on the level in your hole for now - certainly don't refill it just yet. You may need to keep an eye on it for some weeks, certainly until after we've had a few spells of significant rain.  Even then, it may take days or even a week or two to percolate from next door into your property.

By keeping an eye on the level, at some point a light will come on and you'll be able to correlate the level with an event, such as rainfall, although it may take some time for that correlation to make itself apparent.  I'd not expect the true gwl in a clay to respond to rainfall events.  That 'a-ha' moment will then enable you to devise a solution - but I'll bet that if next door had recognised that they have, or have had, leaks, and they've all been or are being fixed then the problem may simply go away now.  Whatever, don't go spending money on a perceived solution until you've understood the cause.  Without knowing the cause, you'll simply be guessing at the solution.

Keep us posted?

PS: I'm not surprised that you can't find anyone to offer a solution. The cause of these sort of problems can be very difficult
to determine and usually takes time, and hence money.  You're the best person to collect the facts, as you are doing, and you appear to have a good grasp of the key factors.   Getting someone in to identify the cause means that you need to find a ground professional, and there aren't that many of us in the UK.  They mostly reside in the major consulting engineers, civil engineering and ground investigation contractors and cost £lots/hr to hire because their clients are almost never private householders.  There's significant professional  risk in advising a householder, for a relatively small fee - it's a risk and reward issue that the indemnity insurers don't like.


Blodwyn Pig

  • what a nice chap
Re: Water table under the house
« Reply #10 on: June 12, 2018, 07:30:24 pm »
some thoughts
a) if its only recent, then it could just be the effects of those cloudburst downpours that happened about about a month ago,  assuming that you got them of course

b) How old is the house? is there /was there a pond in the vacinity

c) is your surface water disposal  a separate or combined system,if separate, then maybe the soakaways ( yours and neighbours are just full up)

d) if its permanently wet,then
option 1) could be to remove the timber floor, room by room, and hardcore/ insulate, dpm, and concrete it, and fill/ replace the air bricks.
option 2) dig a trench around the perimeter, down to say 600mm, and about a shovel width, and fill with P shingle, and continue a trench to the lowest part of the garden, to create a land drain.
option 3) dig down about 1m to  create a foundation trench  along your elevated boundary, and put in concrete footings and build a solid concrete block wall, with tanking to the neighbours side ( 2/3 layers of DPM should suffice) and pea shingle,  so the water from the neighbours land is kept from your house,  and away to the road, via a buried pipe

But of course I haven't seen the house,   If it is a common occurence, I would favour option 1+2

fd3

Re: Water table under the house
« Reply #11 on: June 12, 2018, 09:55:11 pm »
Thanks again andy.
This has been going on since just before Christmas.  If I bail out the water from the hole it slowly fills back up, but not to above the level of the ground.  With two holes dug, one closer to the back door, they seem to fill up at about the same rate despite one being less deep than the other (maybe the shallower one by the back door fills marginally faster).  It will typically refill in a day - but this has varied.  I did keep a log for a bit, when I was trying to see whether it was an issue tied to time of day (e.g. neighbours' water use).  I can say for sure that it's linked to time of day, when we had the prolonged cold spell without rain at Christmas it stopped entirely for a couple of days.  I am definitely seeing less water in the warm weather spell.  There doesn't seem to be a link to whether the neighbours are in or not (in that they were in at Christmas when it stopped).

Between the issue when we moved in and removing/replacing the pipe taking water from the property (which is both household and roof rainwater) they have had everything done at the back.  They do not have some gravel about one of the drains at the back where they used to have pavers, but at most they are getting splashing from a side alcove.

I think in the first instance we will get the airbricks at the back sorted (we only have one airbrick and half of it is level with/blocked by the floorboards).  I'm thinking I'll investigate adding water next, to see whether the level stay high or drops down over time (though it will drop down so why would I do this?  Maybe to see how fast it happens, not sure).  Rain's forecast for Thursday so I'll see if that does anything.

Appreciate all the suggestions.
And we know the flag of love is from above/And we can force you to be free

Aunt Maud

  • Le Flâneur.
Re: Water table under the house
« Reply #12 on: June 13, 2018, 09:05:44 am »
I'm wondering if you're overthinking it a bit, have you checked all the drainage around your house ?

A lot of these problems have simple solutions and your eyes are the best tool you have.

andytheflyer

  • Andytheex-flyer.....
Re: Water table under the house
« Reply #13 on: June 13, 2018, 09:08:34 am »
I can say for sure that it's linked to time of day, when we had the prolonged cold spell without rain at Christmas it stopped entirely for a couple of days.  I am definitely seeing less water in the warm weather spell.  There doesn't seem to be a link to whether the neighbours are in or not (in that they were in at Christmas when it stopped).

Good info this.  If you are definitely seeing less water in this warm weather, that's not a gw issue.  I'd be 95% certain it's water coming from surface water flow.  You'll be seeing less water because there's less rainfall, and /or water leaks are evaporating or being reduced by plant transpiration in the soil layer.  You'd be most unlikely to see level changes in dry weather if it were gw, except over a period of weeks.  If the level changes during the day, it cannot be gw, it has to be surface water related, and almost certainly a leak from a drain.  You would probably  not see any obvious link to whether or not the neighbours are in  because if it s a leak in their drainage, then the flow is likely to be attenuated by the need to flow through the soil layer - the physics of that flatten out the rate of movement curve - taking out the peak flow and spreading it over a longer period of time (flattening out the bell curve if you know any statistics).  Hence the lack of a link to whether or not they are in.  The time of day issue probably also indicates a drainage leak, but with the flow rate attenuated by the ground permeability.  So, you might see an increase in level in the middle of the day as a result of them having baths and using the loo etc at breakfast time, for example.  But, it could be a level rise later in the day from the same cause, but it's taken longer for the flow to reach your hole. 

You mentioned earlier a possible buried channel or similar taking flow from next door to your property.  That's possible (but there's an urban myth about "underground rivers" that most geologists and hydrogeologists will politely ignore and move on!), but is more likely to be due to an old field drain, or service of some sort, long since abandoned and forgotten, but is still providing a preferential flow pathway, even if it's apparently blocked.  That preferential pathway will serve to reduce flow times, and hence increase the peakiness of the bell curve, which makes determination of how the water gets to your hole a bit more tricky.  Hydrogeologists thrive on deconstructing flow curves (hydrographs) to identify water flow paths.

Your observations are very valuable as the time of day/rainfall data very strongly suggests that the source is human-related.  I'd have a look at the chemistry of the water in your hole.  Bale it out and take a sample when it's refilled. Whilst at this point I'd have consulted my hydrogeologist colleagues to tell me what determinands (aka chemicals) to analyse for, I'd look for those that would be in urban drainage water and not naturally in the soil, so E.coli, soaps and detergents, things like that, maybe even the components of the oral contraceptive as we find these now in rivers etc as a result of them passing through sewage treatment works. 

There are plenty of water analysis labs around that do this routinely and will advise on the determinands to analyse for if you tell them what you think the source is (and how to sample if necessary).  Some of them will supply you the sampling bottles and tell you how to sample and store it as some determinands need protection in the stored condition for the few days it takes to get them to the lab and analysed.  I'd speak to your local authority public health office and they will be able to put you in touch with a local lab.  Testing isn't particularly expensive and it may well give you a strong pointer to the source of the flow.

Finally, you might look at the water in your hole and think it's clean - no soap, smell etc - but it's been filtered very effectively by flow through the soil, so you'd not necessarily see anything obvious, but a lab will find concentrations down to parts per billion for some determinands. 

Keep going - you are doing a great job with the observations and getting closer to finding the problem, and then the solution.

And Aunt Maud is right - sure it's not your own drainage ?

fd3

Re: Water table under the house
« Reply #14 on: June 13, 2018, 03:16:46 pm »
Sorry, missed an important apostrophe-t; should have been "I can't say for sure that it's linked to time of day".  I thought it was, but I don't think I measured regularly enough to be able to tell.  Done dye tests (our house and neighbours') and chlorine tests, which both returned null, which is why I don't think it's drains.  If it were my property that would make my life easier as I could do something about it more easily.  I think the local testing place for me would be Birmingham City Labs, I'll look into it, thanks.
And we know the flag of love is from above/And we can force you to be free

andytheflyer

  • Andytheex-flyer.....
Re: Water table under the house
« Reply #15 on: June 13, 2018, 05:56:50 pm »
No matter - the flow attenuation process will delay the flow of water to your holes and so it may not be possible to identify any correlation between time of day and the filling of the holes. 

Whatever, the phenomena you describe indicates to me it's not gw.

Was the cold weather over Christmas sufficient to freeze the soil?  That could explain the lack of recharge at that time.  I don't remember the temperatures then, but in any event it would have to be very cold to freeze the ground more than say 200mm deep.

fd3

Re: Water table under the house
« Reply #16 on: June 19, 2018, 09:13:58 am »
Thanks again for the input.

I have pulled up some of the black bricks in the outside path, the ground below is very hard, but the bit I could dig was pretty dry.  It's earth, not clay though.  At the back the garden level is the same as our neighbours, it's when you get to the house that we are lower (our path is about a foot lower, their house is actually a step up from the path).
Filled the hole in with clay to see whether the water level stayed 2-3 cm below the rest of the level (which is what it was doing) but we are seeing puddles above the top.

We did have one suggestion to lower the path outside, but that would mean removing and relaying all the drainpipes as they are about one brick deep.  Also, not sure the bricks under our house are more than a couple bricks deep. 
The latest person we had in (yesterday) had a measure and pointed out that there is quite a bit of damp, issue with joists etc.  Their first thought was sump pump and a poured concrete floor. 
*Would you need both a sump pump and a concrete floor, or should just one suffice?
*I would have thought that the concrete floor would stop water coming up, but not stop water coming under.  Or if it is deep enough would it push the water along a different path?
*If we install a concrete floor, would we not need to do the whole ground floor?  How can the other rooms get airbrisk through-ventilation if there's nowhere for the air to go? (or can they just use the chimney?).

Thanks for all the explanations, it helps the try and reason it out by writing, even if I still can't make sense of it.
And we know the flag of love is from above/And we can force you to be free

andytheflyer

  • Andytheex-flyer.....
Re: Water table under the house
« Reply #17 on: June 19, 2018, 09:50:41 am »
IMHO, it's almost certainly (you always need 3 opinions from geologists so you get a majority decision) surface water runoff through the soil layer (above the clay) which is running across the top of the clay and ponding at a low point, in this case, under your house.

If it's a new phenomenon, what's changed to give rise to the problem.  Identify that and sort it.

If it's not a new phenomenon, then you probably need some drainage around the outside of the house to pick the flow up and take it away from the building. 

By all means put in a concrete sub floor, but I'd expect the water will simply pond on top of that.  I'm no building surveyor, but you will need to have good ventilation below your floor joists or you will be heading for a bigger problem.

Either find the source and remove it, or intercept it where it enters your house and lead it away.  Anything else is simply dancing around the elephant in the room's handbag on the floor - to mix and mangle a few metaphors. Money spend on that will be better spent than a concrete subfloor. The gravel trench (aka a french drain), say 150mm wide and maybe 500 deep is fairly easy to construct and is more or less maintenance free.



Re: Water table under the house
« Reply #18 on: June 19, 2018, 11:50:55 am »
Like Andy I also deal with ground water as a way of earning a living, although I am on the contracting side of things (so Andy wears a smart suit, I wear old clothes).  I would agree with all that Andy has said, and think that his suggestion of a french drain is probably the best solution if you are not able to identify the source (and I would recommend that you do try and find the source first, it is very unlikely to be "ground water").

I would caution against a concrete sub-floor as concrete is not waterproof (unless you use some very expensive additives in it and even then it can be a bit hit-and-miss) so the damp will still come up through the concrete, but, as Andy says the water will also probably just pond on top of the concrete so you will possibly just make matters worse.

andytheflyer

  • Andytheex-flyer.....
Re: Water table under the house
« Reply #19 on: June 19, 2018, 12:59:51 pm »
Like Andy I also deal with ground water as a way of earning a living, although I am on the contracting side of things (so Andy wears a smart suit, I wear old clothes).

 ;D

Thx LJ - but I'm retired now so the suits have gone back in the wardrobe.  Not that I often wore one - I was a very hands-on site geologist - usually found in a hole somewhere, or up to my elbows in soil or rock samples getting muddy!  I did a few years early on with an SI contractor, so got used to getting cold wet and tired early on.

Completely OT, I was an expert witness on a complex failed landfill project claim a few years ago.  The Plaintiff (my client) appointed a well-known barrister to assist, and I met him one day on a grubby, urban, closed landfill.  He was in a sharp suit and brogues, just up from his London chambers. Needless to say he couldn't walk the site, and he was replaced not long afterwards...….

.....by another London barrister and new QC, who turned up in a torn Barbour jacket with 2 Tesco bags.  Each one had a very muddy wellie in it.  He turned them out, put them on and we walked the site.  I remarked during the visit that he'd obviously come prepared.  Well, he said, I was down a tunnel in Blackburn last week and I've not had a chance to clean the boots since.....  My sort of barrister.


Needless to say, he stayed the full length of the 5 year case, won damages for his (and my) client in an out of court settlement, and is now a very well-known environmental engineering barrister.  Frighteningly clever too.  Now he was a QC I could do business with.  In this business, wearing a suit in front of a client is all very well, but you need to get into the  heart of the problem to understand what's wrong, and that means getting dirty!

Aunt Maud

  • Le Flâneur.
Re: Water table under the house
« Reply #20 on: June 19, 2018, 01:18:08 pm »
I too think you're wasting money pouring concrete.

Have you checked your rainwater drains properly ?

fd3

Re: Water table under the house
« Reply #21 on: June 19, 2018, 01:54:27 pm »
Hi Maud,

not sure what you mean by "properly" checked.  Our rain goes into the same drains as the household waste, which have all been dye tested. 
And we know the flag of love is from above/And we can force you to be free

fd3

Re: Water table under the house
« Reply #22 on: June 19, 2018, 02:04:01 pm »
Photos, not sure if they help
F6C32F95-C3A1-4AA1-93AD-79387E20B1E0 by belgiangoth, on Flickr
At back door neighbour ground level is 4 bricks higher, this drops to 2/3 bricks as you move away (level with the potted bay tree) and then ground is level at the hedge.
D28015F8-F228-4DA8-8FD8-35DE0DE549BC by belgiangoth, on Flickr
Brick-paved path slopes towards gutters.

Wooden floor is level with path outside, with about a foot air-gap to the soil below.  Kitchen (left from path) is poured concrete and also level with the path.  No issues there.

The guy who was going to fit a french drain couldn't link it to the drainpipes as they are higher than the clay soil level (hence the idea of a sump pump).  He reckoned that he would need to dig the end about 4' deep to be able to get gradient for the flow of water away from the house.

I wonder whether it would not be possible to have something more like a step in level, if the water flows down out of the house and then across along a flat level, as long as there is a lower drop garden-side it will flow away. ... or not?
And we know the flag of love is from above/And we can force you to be free

Re: Water table under the house
« Reply #23 on: June 19, 2018, 04:44:54 pm »
Is there any new development nearby? Without reading all of the thread again has anyone mentioned bentonite slurry?
Get a bicycle. You will never regret it, if you live- Mark Twain

fd3

Re: Water table under the house
« Reply #24 on: June 19, 2018, 05:50:53 pm »
Is there any new development nearby? Without reading all of the thread again has anyone mentioned bentonite slurry?
No and no.
And we know the flag of love is from above/And we can force you to be free