Lowering Ground Level - Shallow foundation damp

[zaceverett]

Can any help on a problem i have with my solid walled turn of the century cottage.

A room at the front is damp so i removed the gyproc stud walling which was mouldy and wet.I also removed laminate flooring which was bowing and bouncy, there was moisture underneath on the concrete slab floor. The walls were also covered in a cement based render internally which was craking off so i've tried to remove as much as possible.

Here is a photo of the outside. I have lowered what was a raised path, where the mud is on the wall is where the path was in contact with it. This has started to dry out.

I wanted to lower the path to 6- 12 cm below internal floor level. However i dont seem to have any foundations under the, what looks like a stepped brick.

I have damp at the areas on the bottom of the internal walls.

I also have a cracked concrete floor i can see the soil underneath

What can you suggest i do to remedy the damp at the base of the walls, how to replace the cracked concrete floor.

The damp man has registered damp on a completely internal wall on this room. Is there a possibility that moisture is rising up from the ground level internally?

I would like the room insulated some how with plasterboards but really don't want to trap any moisture behind.

Any help appreciated or if anyone knows any good builders that could be of assistance in the Warwickshire area that would be great.

Zac

 

[Roger H]

Hi Zac,

I’m sure you will get lots of suggestions here. Clearly the damp issue has been there for some time hence the evaporating tubes (?) that someone has inserted into the wall. On the floor, at least if it is already cracked there is less of an issue for you on ripping it up and tackling the problem comprehensively. Also enabling insulation under the new slab.

I’d suggest excavating a very small section to determine exactly how deep the foundation sits, both externally and internally. Then you can work out how much space you have to play with and informing what options may be available using the present depths.

Removing the path abutting the wall will certainly help reduce damp in the walls. If it were mine I’d rip the internal concrete out too as it is damaged and laid straight to earth. If you have enough depth inside you get some free draining material under the floor, insulation, new screed and so on. Breathable floors without dpm are also an option. Have a look on the threads re damp meters. I’d not be inclined to worry re his readings on internal walls.

Where do the internal ground levels sit in relation to the outside photo?

 

[Zebra]

This looks familiar to me! I'd agree very much with Roger. I had very much the same problem, and had to try onen thing, wait to see whether it had worked, then try another. You will solve the problem in the end, but it might require patience. Lots of it! My house has another two courses of brick under the one which is stepped out - four courses in the corners - so have a bit of a dig in a small spot, there might be something down there. You could take the concrete floor out just around the edges to begin with - a "breathing trench" (leave the bit in the middle to walk on) and see whether the damp in the walls is improved. Lowering external ground levels to 150mm below internal is important too.
Yes it is possible that moisture is rising up through soft porous bricks in internal walls. But I would say beware of getting a builder in to tackle it if you are concerned about using traditional methods or helping the house to breathe in the way it was designed. A builder will probably suggest an injected dpc, internal tanking and then insulated plasterboard, which might not help and may make the problem worse in the long run.

 

[zaceverett]

Thanks for the advice, I'm going to have a excavate may be a foot section both inside and outside to see if i can locate any footings.

I would like to relay the floor properly, limecrete any good? IS it possible to do yourself?

Went out this morning and found this

Guess this is standing water, has rained a lot but cant be good. Do you think a land drain/french would handle this. If so as i have vshallow foudnations or non at all how close do you think i should install it to the building?

 

[Penners]

Zac - I very much echo what has been said by Roger and Zebra above. You have a classic damp problem, and you've made a good start on resolving it. However, I do urge patience - the problem with damp is that the results of remedial work can take a very considerable time to become apparent, because the masonry takes so long to dry out. And this winter's weather is only going to prolong the process.

The outside path was undoubtedly a significant contributor to your damp, so its removal can only be beneficial. You obviously recognise that, if possible, the bottom of your excavation should be below internal floor level. The stepped out brickwork that you have discovered may not be the bottom of your foundations, but the only way to find out (as Zebra suggested) would be to dig a small pit and see what you find. On no account should you do your general excavations any lower than the bottom of your foundation.

The brickwork abutting the trench looks as though it has some kind of cement slurry coating on it - you would aid the drying our process if you could get this off, but if you can't remove it without significant damage to the bricks, then I shouldn't try.

Internally, I presume that you plan to hack off any plaster that's on the brickwork. This would also make an important contribution to the drying out process. Try to get the bricks "naked" up to a height of about 1 metre, if you can.

There's obviously not much of a concrete floor, so I would certainly rip it up. It is likely to be causing ground moisture to migrate sideways to the walls, making a further contribution to the damp in their dampness. If you have sufficient headroom, then a new suspended wooden floor may be the best solution, so long as you ensure that the void underneath is well ventilated by crossflow grilles in the brick plinth. Be sure to use pressure treated timber for the joists, isolate the ends from the brickwork with damp-proof membrane material and insulate between the joists under the floorboards.



An alternative solution for your new floor could be limecrete, which will allow breathability for the subsoil, and because it uses a foamed aggregate it will insulate your floor.

http://www.limecrete.co.uk/limecrete.asp

However, I'm not sure whether you have sufficient depth of floor available to use this, so I would be inclined to take professional advice on it.

 

[MatthewC]

Hi Zac

All your photos look very familiar to me. I agree with all the above advice, especially that you must be patient as it takes a good while for the wall to dry out, but lowering the ground level is the way to go. You can safely excavate just a small length of wall to be sure of the foundations, say 9-12 inches wide.

For indoors, I would recommend a limecrete floor, but then I would, as I've done one! See my blog http://houseintheenchantedforest.blogspot.co.uk/2011/04/fitting-limecrete-floor-part-1.html

Never trust "specialists" with meters!

Matthew

 

[jackpoint]

Sounds like a similar story to us, and the wall construction is very familiar. We lowered the ground level and things did start drying out...........then it rained. And rained and rained and rained. You know the story. So now we have penetrating damp instead :lol:

 

[plasticpigeon]

If you find good builders in the Warwickshire area, please let me know too. I can tell you who to avoid!!!!

 

[zaceverett]

Ok struggling now, anybody in the warwickshire midlands area that can lay a limecrete floor?

And install breathable wall insulation.

Just cant find any builders.

Any help appreciated.

 

[CliffordPope]

This seems such a common problem, it makes one wonder why builders in the past didn't elevate floors a few inches clear of ground level, rather than sinking them in holes. Didn't people care about damp then, or have houses generally sunk over the years?
If the latter, then the only fundamental options seem to be massive landscaping to lower the whole garden level by a foot or so, to follow the house downwards as it were, or else to build the floors upwards, if there is the headroom.

If houses generally are sinking, then they will all have to be concreted and tanked one day

 

[Keithj]

Who can do a limecrete floor? Give Ty Mawr a call, tell them where you are, and ask who they know in your area.

I'm lucky: in this part of Suffolk there are several who know (but there are an awful lot of listed properties around).

Anyone who suggests "tanking" or "injected DPC" should be sent on his way. A friend of mine had an injected DPC; it didn't work; the supplier is now telling him he should have had the expensive version and is coming back to drill lots more little holes and fill them with resin. I tried reasoning with him but the other bloke is "a professional".

 

[plasticpigeon]

Re limecrete. I think anyone that can lay a concrete floor can lay limecrete. There is nothing special about installation. Ty Mawr can send everything that is needed and they also send instructions. They say to make the mortar very stiff in a pan or screed mixer, but at mine the mix was done in a conventional rotating mixer and everything was fine, no cracking at all. Obviously it shouldn't be a slurry, but loose enough not to ball up and it should be fine. You just need manpower really, and i thin there are agencies where you can hire a labourer for a day or 2!

 

[zaceverett]

I gave Ty mawr a ring and spoke to a chap who said he'd have a look for me and get back with some builders.
I sent them an email with a few details explaining what I required and if they knew any local builders.

Haven't heard diddly squat in 4 days so presume they must be busy.

Hey ho.
Looks like i'm going to have to get a local conventional builder and see if i can persuade them to use limecrete and give them any instructions ty mawr or any one else can send.

Never having tried to lay a floor before, i dont think i'd be able to give it shot myself.

These are the latest photos from the problem room. I've done some more stripping back to brick.

This is an old door way which is boarded in and not used.

Mess of wire in ceiling. This room used to be a kitchen and all the old heavy duty wires for the kitchen appliances and been left connected.

This is a problem wall which was soaking. It did have a raised outside ground level which i've dug back to the foudations. You can see the concrete screen on top of the black plastic floor tiles.
This whole concrete floor is cracked and only a couple of inches thick laid onto soil. This is what i want replacing with limecrete. Having v. shallow footings it has been suggested that i 'bowl' the room out.

 

[Lime]

This seems such a common problem, it makes one wonder why builders in the past didn't elevate floors a few inches clear of ground level, rather than sinking them in holes. Didn't people care about damp then, or have houses generally sunk over the years?
If the latter, then the only fundamental options seem to be massive landscaping to lower the whole garden level by a foot or so, to follow the house downwards as it were, or else to build the floors upwards, if there is the headroom.

If houses generally are sinking, then they will all have to be concreted and tanked one day

It is the exterior ground level that rises over time not that the house sinks.
Waste collection was rare in the past.
When open fires were common the ashes were strewn all over convenient areas outside.
That meant that many tons of material were dumped around a house in just a few years.
The earth worm played a major role in burying most of the cinders and dust.
(How do you think Roman remains became 12-20 feet under ground?)

Even today when removal of material is relatively easy to do most people still opt for the easy and quick way out.
Shingle, paving, wood bark, cement, decking, tarmac, tiles et al are all usually placed on top of what already exists.
It is rare that a large amount of original material is removed beforehand.
Hence the increase in ground level.

Fortunately most houses can have their exterior ground level lowered relatively easily so the need for the modern inappropriate short-term solution of concrete and/or tanking is an unnecessary expense.

 

[zaceverett]

Just cant find anyone local to warwickshire who can lay a limecrete floor.
Or install breathable insulation.

Most builders quoting me are going down a sealed membrane against the wall and then allowing the condensation out through holes etc.

I'm really stuck now, I don't have the skills to do it myself so I guess I'll have to resort to concrete and conventional methods.


HOLD FIRE...

Ty Mawr have just come back with some local contractors. Might be onto a winner here. I'm sure you're all really interested

 

[Zebra]

Yes we are Zac. Hang on to your idea of what you want. Don't let conventional builders talk you into doing things their way. Modern methods work fine for modern houses. Be persistent, decide what you want, and then find someone to do it for you, not the other way around.
I've said this before, so I might have said it to you already, but I've found that younger contractors are sometimes easier to convince. Get the materials, get detailed instructions from the supplier, and then find someone with the skills you need to apply it. You'll be glad in the end.

 

[paulb33]

When it comes to damp, folks are quick to blame 'penetration'. Whereas, condensation is frequently overlooked.

I'd be replacing those uPVC windows and the cement plasters/renders. Heat and ventilate.

CAVEAT: I KNOW JUST ENOUGH TO BE DANGEROUS

 

[MatthewC]

I've said this before, so I might have said it to you already, but I've found that younger contractors are sometimes easier to convince. Get the materials, get detailed instructions from the supplier, and then find someone with the skills you need to apply it. You'll be glad in the end.

Well said. I found some 27-30 year olds for almost all the jobs in my house and they were excellent. My limecrete floor was done with me passing on the wisdom from Mike Wye to two young and fit lads who had skills in using a mixer and laying the stuff, and who listened to the wisdom. A good combination.

 

[Zebra]

I find that younger contractors can be full of enthusiasm for trying products they've never used before. My roofer was an antelope in his late 20s, and the exterior renderers were a pair of hyenas of a similar age.

 

[paulb33]

Isn't there a forum law against all this ageism? :?