Damp concrete floor in extension, tiles breaking

[cammy0102]

Hi guys, I was wondering if you could provide some guidance dealing with a very difficult situation I'm in.

Some of you helped me with another issue (broken drain pipe) here:
http://www.ukplumbersforums.co.uk/p...-sewerage-pipe-garden-options.html#post913865

It's probably going to be a long post to explain the situation so bear with me please.

I have a ground floor 2 bed Victorian garden flat (period conversion) in West London. I bought this flat about a 14 months ago and did a full refurbishment with new plumbing, heating, flooring, bathroom and kitchen.
There's an extension at the back of the house (I think this was probably built in the 80s when the house was converted to 2 flats) that houses the bathroom and the kitchen.

Here are couple of pictures to give you an idea of the layout

House, garden, patio and drians - Album on Imgur

Flat layout

Current situation:

About 6 months ago I started noticing that a floor tile in the bathroom was starting to crack. This gradually got worse with this tile lifting up then spreading to a couple of other tiles around it.

Tiles cracking and lifting up

Last Saturday, I my builder's men came around to have a look. They removed about 6 floor tiles and we found that the concrete floor underneath was quite damp and concrete was crumbling (mostly where the tile first started cracking) and still quite damp nearby as well (though not as much).

Damp concrete floor in the bathroom

The guys weren't really sure what was causing the damp. Initially I was thinking it was a leak from a pipe in the floor but according to them, there weren't any pipes going through the floor in the bathroom and the new pipes installed were in the walls.

There were 3 possibilities for the damp according to them -
1. The water pipe connected to the sink tap or the pipe taking waste water away from the sink (both of them are in the wall) is leaking and this water is going to the floor down the wall and is saturating the floor.
2. water leak from the toilet in to the floor
3. The floor in the extension wasn't made properly and is getting damp

They reckon if it's a leak from the toilet or pipes in the wall, it's easy enough to fix. I'm stressed that the damp in the floor is due do a badly built extension. We left it for a few days to see if it dries out and then go from there.

Background and possible causes

When I bought this flat, the day I got the key, I found that there was a leak from the old bathroom and there was a lot of water on the the bathroom floor and living room floor and all the surrounding walls saturated. If I remember correctly, where the new tiles started cracking was roughly where the old pipe was leaking (they were in a box so we had to break the box and to see the leak and then stop the water mains).

We started renovations about a month later and I remember the walls in the living room near the bathroom had damp patches that didn't dry out so I had to get damp proofing people to hack off plaster and add water proof plaster in the living room.

My builders removed the old floor tiles from bathroom and kitchen. Partition walls in the bathroom and kitchen were also removed and new walls installed. I don't remember much about the concrete floor in the bathroom but I do remember the kitchen floor (after the old tiles were removed) looking a bit damp and the plumber kept saying the floor was quite wet. This guy was there last Saturday and I mentioned about the kitchen floor but he said the kitchen floor did try out mostly eventually.

My building survey at the time of the purchase, highlighted high ground level outside, at the back of the house. Also it was paved right up to the building with no gap.
At the time, I didn't know about damp issues so I didn't think of much of this. But because of the damp walls I had, recently I decided to lower the ground level in time for winter so got a new patio few weeks ago. My landscape gardeners removed the old patio (had paving bricks on one half and concrete slabs on the other), reduced the ground level by 10-20 cm and put in a new patio with a 'french drain' (I am not sure if this was a proper french drain but more about this later).

My landscape gardeners also mentioned that, previously waste water from the plastic pipes outside the bathroom (carrying waste water from the bathroom and kitchen) were let straight on to the old patio (brick paving) and that this water was not connected to a drain. I am not sure how many years it was like this but it's possible this water was going in to the building perhaps causing some of the damp issues. When new patio was installed, my landscape gardeners installed a gully in the patio to collect the water from these 2 waste water pipes.

The flat roof on the extension was really old and was probably leaking as well. I remember there was a lot of mould on the walls in the kitchen and bathroom.

It's worth mentioning that tiles in the old bathroom and kitchen seemed fine and I can't remember seeing any cracks. So this damp floor might not have been there for years (you'd think the old tiles would have cracked if the floor was damp for a long time).

The fact that the tiles started cracking in one area (and the concrete is crumbling around this) plus tiles only started cracking this year suggest that this might be caused by a leaking pipe or toilet but then what caused the kitchen floor to be damp, during renovations? Maybe it was the water from the big leak at the time of the purchase or water leaking from the roof. Maybe there are multiple factors here.

Hope it's not too confusing for you to understand. What do you guys think? What could be causing the dampness in the floor? How should I go about investigating/fixing this?

I guess my worst fear is that the concrete floor in the extension wasn't installed properly and the moisture is rising from the saturated ground. If this is the case, to fix the floor, I'd have to rip out the new kitchen and the bathroom which I don't really want to do!

French drain

OK finally the french drain..I told landscaper gardener I wanted the ground level reduced (with a new patio) and a french drain that went around the back of the house and the extension.

New patio, gully and french drain

But all he's done is leave about a 10-12 cm gap between the house + extension and the patio and back filled it with gravel. So the french drain isn't any deeper than the depth of the patio + type 1 base. I'm guessing this is about 15-20 cm deep maybe less. The new ground level is about 10 cm lower, near the extension and about 20 cm lower near the living room. Do you think the 'french drain' needs to be deeper?

Thank you in advance for your input and apologies again for the long post.

PS: I bought an EcoAir DD122 dehumidifier start of this year because of the damp problems I had. I left this in the bathroom last couple of nights so the floor might dry out but so far I haven't seen a difference. problem is because there's no power socket for it in the bathroom, i have to plug it in the kitchen so I can't close the bathroom door properly hence it's not fully closed. Could I get an adaptor for the shaver socket and plug the dehumidifier in to this?

 

[joni os]

French drain in London clay needs perforated/slotted pipe connected to a piped drain run . If connection is to foul water drainage, connection must be via trapped gully to prevent smell of sewer gas.
Internally a 1980s concrete floor should have been laid on polythene DPM. Often floor was finished with 2" sand/cement screed. Water does not soften concrete but a sand/cement screed, shy of cement, will crumble.
Having checked all internal pipes for leakage, check pipes going through wall are not cracked and filling cavity with water. Although unusual, plastic waste firmly fixed in external brickwork can shear in cavity.
Fix screed before relaying tiles.

 

[tamz]

Well that was truly a long read and was hard to keep focused. At least you split itinto paragraghs.
I doubt if your problem is plumbing related Looks like heave from no or badly fitted dpm.
Btw your floor tiles look like wall tiles not that it would make any difference except they break easier

 

[cammy0102]

French drain in London clay needs perforated/slotted pipe connected to a piped drain run . If connection is to foul water drainage, connection must be via trapped gully to prevent smell of sewer gas.
Internally a 1980s concrete floor should have been laid on polythene DPM. Often floor was finished with 2" sand/cement screed. Water does not soften concrete but a sand/cement screed, shy of cement, will crumble.
Having checked all internal pipes for leakage, check pipes going through wall are not cracked and filling cavity with water. Although unusual, plastic waste firmly fixed in external brickwork can shear in cavity.
Fix screed before relaying tiles.

I asked the landscape gardener about perforated pipe but he said there was no where for wter to go and also said it was illegal to connect it to the main drain. But I already had everything (including rain water from gutters) going in to the main drain.
Should I ask him to make it deeper and install a perforated pipe?

If it's an issue with the floor and not any leaks, is there anything else I can do? Will the french drain help?

 

[cammy0102]

Well that was truly a long read and was hard to keep focused. At least you split itinto paragraghs.
I doubt if your problem is plumbing related Looks like heave from no or badly fitted dpm.
Btw your floor tiles look like wall tiles not that it would make any difference except they break easierView attachment 28358

So you think it's the floor? Thing is I didn't see the previous tiled floors of the bathroom and kitchen cracked. And why is it very damp in one area?

Even though the new bathroom tiles have cracked, the new kitchen tiles (albeit) so far haven't.

I know they look like some of the wall tiles but they are definitely floor tiles.

If it's a floor issue (terrified this might be the case) what do I do? How can i tell for sure it's the floor?
Are there any specialist companies/surveyors that deal with these sort of issues?

 

[cammy0102]

I forgot to mention that the floor tiles in the kitchen (bigger tiles) so far haven't cracked but they do seem a bit cold but that could be standard.

 

[joni os]

If rain water goes into main drain then it is a combined sewer and will take water from French drain. Floor can be tested by hammering in 4" nail. Nail will penetrate screed but not concrete.
This should indicate extent or limit of your problem.

 

[cammy0102]

[FONT=&quot]Another thing to add. When I tap on the couple of floor tiles next to the affected area they sound hollow but other areas of the bathroom sound solid![/FONT]

 

[cammy0102]

If rain water goes into main drain then it is a combined sewer and will take water from French drain. Floor can be tested by hammering in 4" nail. Nail will penetrate screed but not concrete.
This should indicate extent or limit of your problem.

What's a nail going through the floor going to test though? If there's a DPM, wouldn't it damage it?

 

[joni os]

What's a nail going through the floor going to test though? If there's a DPM, wouldn't it damage it?

It will establish what is screed and what is concrete. If it goes straight through to DPM then you will know:- The whole floor needs redoing and existing will break out easy.
If it penetrates 2" and then buckles you have a 2" screed topping an acceptable concrete oversite. and replacing screed under broken tiles may be limit of works.

 

[cammy0102]

It will establish what is screed and what is concrete. If it goes straight through to DPM then you will know:- The whole floor needs redoing and existing will break out easy.
If it penetrates 2" and then buckles you have a 2" screed topping an acceptable concrete oversite. and replacing screed under broken tiles may be limit of works.

Sorry for my ignorance. Is the DPM under the concrete then? Is it DPM, Concrete and screte from bottom to top?

 

[joni os]

Sorry for my ignorance. Is the DPM under the concrete then? Is it DPM, Concrete and screte from bottom to top?

Hardcore ; DPM ;Concrete; Screed. was normal for 1980s build. A 4"nail should not penetrate any DPM.

 

[cammy0102]

Hardcore ; DPM ;Concrete; Screed. was normal for 1980s build. A 4"nail should not penetrate any DPM.

Ahh OK gotacha. thanks.

 

[cammy0102]

If it's not a current plumbing leak, it's still possible that it was water that was trapped in the floor (screed) from the previous leak about a year and half ago especially since that leak was very close to the currently affected area. In that situation I'd imagine it's difficult to say it's a badly laid floor or it's the water from previous leak trapped in the floor. How do I proceed in that situation? Can I just remove the floor tiles in the bathroom and install waterproof membrane and re-tile?

 

[sparkie30]

If it's not a current plumbing leak, it's still possible that it was water that was trapped in the floor (screed) from the previous leak about a year and half ago especially since that leak was very close to the currently affected area. In that situation I'd imagine it's difficult to say it's a badly laid floor or it's the water from previous leak trapped in the floor. How do I proceed in that situation? Can I just remove the floor tiles in the bathroom and install waterproof membrane and re-tile?

You best take tiles out then take about 100mm or more off screed/concrete then lay dpm and 75mm celotex then screed then electric underfloor heating then tile.

Decent job me thinks

Good luck.

 

[Radioman]

If you can rule out a water leak from feed or waste pipes that would be good. Then If the damp area is situated around the old brick wall that was originally an external wall of Victorian age I would guess that there was no DPC on that wall. Hopefully Whoever did the extension was supervised by building control and put in a physical DPC on the new walls and floor but probably didn't bother on the existing wall or maybe did a chemical injection that has now failed. Excavate and replace as above and then knock off all plaster up to 1 meter and re inject.

 

[Frog67]

Drain test should sort out if plumbing related.
As stated above, your gonna have to dig into floor to examine oversite.
Check outside for damp course in brickwork and how low the patio slabs are from this level. From memory the slabs should be 150mm below.

 

[lame plumber]

could just be you laid tiles on a damp base, seen it before, new concrete not left to dry long enough, I would start by removing tiles, cleaning up base and see if it dries or if there is an underlying issue. take your time

 

[cammy0102]

As I mentioned before, the old floor tiles in the bathroom and kitchen seemed to be fine and I didn't notice any cracks. So if it's been damp for a number of years surely those tiles would have cracked too?

I've contacted the council to see if the original owner in the 80s acquired Building control for the extension. They charge about 50 pounds to do a search!

 

[Radioman]

Hard landscaping should be a minimum of 2 courses of bricks below the DPC , more if possible. A Henry French Drain should be at least 300mm deep and 150mm wide and constructed like this

 

[cammy0102]

Hi guys,
another update. My builder's guys came back on Saturday and they removed more tiles from the floor (floor seems to be damp everywhere), removed the toilet, removed a tile from the side of the bath.

They then had a look under the bath and put the toilet back on and left but said they'll come back in a few days to see if it would dry out.

Here are some pictures I took
Damp bathroom - Album on Imgur

The floor there seems to be even more damp under the bath than under the tiles of the floor (outside the bath). This could have been partly due to all the water that was coming in to the building from the waste pipes outside which are directly outside the bathroom (previously all the water from the waste pipes were going on to the patio and probably back in to the building but this has been fixed with a new patio and a new gully to collect water) but I reckon there's still a leak in the pipes in the bathroom.

One thing I forgot to mention before, is my brand new combi boiler installed by these guys end of last year, has been continually losing pressure in the last couple of months (since I started turning heating on again). I have to keep topping it up every 5,6 days. For example last week I put the pressure up to 1.5 but then it went down to less than 1 in 5 days. Can anything other thing a leak cause the boiler to lose that much pressure?

I could also see that the pipes had green/blue stuff on them. Does this mean there's definitely a leak or could they be oxidizing because of lot of moisture in the air under the bath?

When I saw this on Saturday I was very worried, thinking the brand new copper pipes are starting corrode everywhere. I don't know if the plumber covered the copper pipes in the walls and floor with material before adding plaster. If they are not covered, could the copper pipes in other parts of the house (say the living room) corrode/leak in a few years time? Or will they still last decades?

I really don't know what to do. I emailed my builder and told him I'm really worried/stressed. He said he'll sort it out.

I even thought of getting an independent surveyor to come have a look but I am not sure they are going to help me resolve this. They might not tell me more than what I already know.
I spoke to a 2nd builder whom I trust and he reckons I should just let my build resolve this.

What do you guys think?

 

[joni os]

Get rid of all those flexible bends. The ones that look like concertina. Including one off toilet.
If not leaking at the moment they are a leak waiting to happen.

 

[cammy0102]

Get rid of all those flexible bends. The ones that look like concertina. Including one off toilet.
If not leaking at the moment they are a leak waiting to happen.

The white one where waste goes? What should I have instead? A leak from this would easily show up on the floor tiles I'd imagine.

Any comments on rest of my update/situation under the bath?

 

[Radioman]

What I think he means is the flexible waste pipe from the bath and the wc. I must say the plumbing looks very rough, more a Builders plumbing than a plumbers plumbing. The green and blue on new copper pipes could be from solder flux not being washed off. If it's on old copper then it could be the dreaded blue spot corrosion.

Water leaking from the boiler could be the source of our damp. Any heating pipe runs near the damp area?

 

[cammy0102]

What I think he means is the flexible waste pipe from the bath and the wc. I must say the plumbing looks very rough, more a Builders plumbing than a plumbers plumbing. The green and blue on new copper pipes could be from solder flux not being washed off. If it's on old copper then it could be the dreaded blue spot corrosion.

Water leaking from the boiler could be the source of our damp. Any heating pipe runs near the damp area?

I got them to replace all the plumbing in the house and I trusted them to do the right thing
So far the contractor/builder has been helpful though and wants to find and fix the issue but I'm stressed and frustrated it's taking a while.

Yep there are heating pipes that run along the wall next to the bath.
How can you isolate the problem though? I've heard of thermal imaging and gas tests to find leaks. Are these expensive?

 

[Radioman]

Given the issues you are having and the direction this seems to be going I would suggest that you politely ask your builder who I assume is the main contractor, for a hard copy of his public liability insurance. I would also ask him if the plumber he employed is actually on PAYE as an employee or is he sub contracted self employed. If the latter get his insurance too. This may seem drastic but I can assure you it is very necessary as if you don't get a resolution and they walk away you will have a devil of a job to get any compensation.

You need to get the ch heating sorted asap as a priority. As the boiler is 12 months old it needs a service so you could get that sorted at the same time by a gas safe engineer. The leak may be inside the boiler but more likely from a pipe joint.

Another simple check would be to turn off all water outlets and observe the water meter to see if there is still flow.

 

[PlumbBobBob]

where is the water coming from that is forming droplets on the bottom of the bath?

 

[oz-plumber]

That isn't damp - that's borderline flooding.

Definitely a leak somewhere.

I would be contacting your insurance company for advice on the situation.
I would even ask them to send out an assessor.

I would say from the photo's, that the bathroom will have a lot more damage done to it to find and repair the leak(s). You could basically be in the same position as you were when you decided to have it re done.

Do you think the builder will re-start the process from the beginning?

That's where you insurance company may be of assistance - getting his insurance company to pay for the repairs

 

[cammy0102]

You guys are scaring me. Claim on insurance already even though the builder is willing to find the problem and fix it?

I don't think the builder can walk away (even if he wanted to) as we have a contract (well it's all in emails) and I don't think he's that sort of guy. He's doing big refurbishments all over London in properties far more expensive than mine.

I think the plumber worked for him (probably not a qualified plumber but someone that has a lot of experience) is one of his employees. I reckon he pays all of his guys (they've worked for him for a while) a daily rate.

I don't think I have a water meter at the property. I pay a standard fee every month to Thames Water.

Can anyone comment about thermal imaging/gas tests to pinpoint a leak?

 

[oz-plumber]

I don't think the builder can walk away (even if he wanted to) as we have a contract (well it's all in emails) and I don't think he's that sort of guy. He's doing big refurbishments all over London in properties far more expensive than mine.

I think the plumber worked for him (probably not a qualified plumber but someone that has a lot of experience) is one of his employees. I reckon he pays all of his guys (they've worked for him for a while) a daily rate.

As for a reply:

The standard of plumbing done, from the pics provided, does leave a lot to be desired.
Flexible waste connections, the bath waste flexi runs uphill. It should have fall from the outlet of the trap.
Concealed flexible water connections - installed where you have to remove tiles to access them.

As for the insurance - I would contact them as soon as possible.
If that's the standard of work being done at your place and places that are worth a lot more than yours, I would be contacting my insurance company sooner rather than later.

Better to be the first in and get a claim before someone else send him broke.

Once he's broke - contracts are about as useful as soiled toilet paper!

Guess who pays for rectifications then......You!!

 

[rupertwelliams]

I was scanning the thread about tile breaking. Good thing, I found this. I also didn't go through my DPM.

 

[cammy0102]

As for a reply:

The standard of plumbing done, from the pics provided, does leave a lot to be desired.
Flexible waste connections, the bath waste flexi runs uphill. It should have fall from the outlet of the trap.
Concealed flexible water connections - installed where you have to remove tiles to access them.

As for the insurance - I would contact them as soon as possible.
If that's the standard of work being done at your place and places that are worth a lot more than yours, I would be contacting my insurance company sooner rather than later.

Better to be the first in and get a claim before someone else send him broke.

Once he's broke - contracts are about as useful as soiled toilet paper!

Guess who pays for rectifications then......You!!

Isn't that flexible waste pipe from the bath connected to the overfill at the top of the bath and then connected to the waste pipe at the bottom of the bath? If so it's not running up hill, it's taking waste down.
I have just emailed the builder and will ring him later. I mentioned to him about the flexible pipes.

To be honest, I don't think he's going to go broke any time soon. He's got multiple teams working for him on various projects across London and he's been doing refurbishment work for a good number of years. And I know most of his clients are happy (I saw a couple of projects before I gave him the job). It might have been this particular 'plumber' he used for my flat. But yes he's responsible for the work carried out by his men. I don't think he actually checked their work.

One thing I don't want to do is rip out everything and re-do it all which will take at least a couple of months. I went through a lot of stress during refurbishment and don't want to go through that again.

The other builder I spoke to said get the issue in the bathroom resolved and if there are no problems in other areas then don't stress about it. He said give my builder a chance to fix the issue. I also got this guy to check the flat after the refurbishment (albeit the cosmetic stuff) and he was happy with the finish.

If this is not resolved, then I will get insurance involved but not just yet.

 

[PlumbBobBob]

I think you should let your insurance know that you may be claiming to give them a heads up

 

[oz-plumber]

In that case, when you find out where the water is coming from, let us know.

You've had the pan removed, tiles ripped up from the floor, tiles ripped off the walls, apparently new plumbing throughout, surface water under the bath, surface water on top of the new tiles and you've requested information on unobtrusive leak detection.

But...your happy with the work done and the work performed by the builder.
And you even admit that the person who did the Plumbing may not be qualified.

If I were you, I wouldn't only be getting my insurance company involved, I would also be getting legal advice.

 

[cammy0102]

Sorry but your solution sounds like a knee jerk reaction. I would have gone with insurance if the builder wasn't cooperating but he is.

There could have been multiple issues contributing to damp - water trapped in the old floor from previous bathroom floor, poorly built floor in the extension and no DPM, higher ground level outside the bathroom and waste water going back in to the building and finally a leak.

There's no surface water on top of the tiles (the water you saw on the tile was the water in the toilet brush container which I accidentally knocked over).

I made an insurance claim for damaged drain pipes in the garden only a couple of weeks ago so not so keen to jump on to another claim without giving the builder a chance to resolve it.

I asked about leak detection tests as builder mentioned this. I am certainly not going to pay for this - it will be up to him to use whatever method to find the leak and fix.

I suspect the builder's guy will have to remove the bath and possibly a couple more tiles from the wall.