Damp, tanking?

Hi Guys, and Gals.
new to this forum and have recently bought a stone cottage which originates from 1800 and something.
The walls are 600mm thick and appear to be suffering from rising damp, mainly affects the plaster about 300mm up from the floor.

I am not convinced on an injected DPC and would rather 'tank' it from the inside, although all tanking products boast about holding 7bar of water pressure etc.

However i dont have any pressure as such as its rising damp, so i was thinking of sand/cement render with waterproofer in, and then plaster over the top.

Any thoughts?

Thanks

Your going to need to LIME render everything, not sand and cement and waterproofer. Wait till a lime expert gives you advice on here, peaps is quite knowledgable.

brad

Lime's no good for tanking.

What i mean is dont tank it, and lime render it. Your cottage is made of lime if its that old and they didnt have wickes and bags of cement then. You could tank it, but your walls need to breathe, and tanking will stop that. Again im no expert on lime. Wait for someone with good knowledge to answer!

Define what you mean by 'breathe'. In the modern world it makes no sense.

Defintion of the word Breathe (br)
v. breathed, breath·ing, breathes
v.intr.
1. To inhale and exhale air, especially when naturally and freely.
2. To be alive; live: A nicer person has never breathed.
3. To pause to rest or regain breath: Give me a moment to breathe.
4. To move or blow gently, as air.
5. To allow air to pass through: a natural fabric that breathes.
6. To be exhaled or emanated, as a fragrance.
7. To be manifested or suggested, as an idea or feeling: A sense of calm breathed from the landscape.
8. To reach fullness of flavor and aroma through exposure to air. Used chiefly of wine.
9. To require air in the combustion process. Used of an internal-combustion engine.
v.tr.
1. To inhale and exhale (air, for example) during respiration.
2. To inhale (an aroma, for example): breathe the lush scent of lilacs.
3. To impart as if by breathing; instill: an artist who knows how to breathe life into a portrait.
4. To exhale (something); emit.
5. To utter, especially quietly: Don't breathe a word of this.
6. To make apparent or manifest; suggest: Their manner breathed self-satisfaction.
7. To allow (a person or animal) to rest or regain breath.
8. Linguistics To utter with a voiceless exhalation of air.
9. To draw in (air) for the combustion process. Used of an internal-combustion engine.
Idioms:
breathe down (someone's) neck
1. To threaten by proximity, especially by pursuing closely.
2. To watch or monitor closely, often annoyingly: The boss was breathing down my neck all morning.
breathe easily/easy/freely
To be relaxed or relieved, especially after a period of tension.
breathe (one's) last
To die

So that's what he meant.

1. A cottage of that age would have outer and inner stonework infilled with rubble. I presume that the exterior is not rendered? What's the condition of the pointing?

2. Tanking up 1m is an expensive possibilty, but could create knock-on difficulties.

3. Rendering up 1m with a 4-1 or 3-1 S&L mix, would be the way to go. Scratch and float coats. Skim with remedial or board finish. Be alert to pulling the render out too far. Stop the render 25mm off FFL. Think about how you will fix rads etc.

4. Why not try it in one room only and see how you get on? dont re-decorate or fix skirting. You will have to wait and watch for 6 months or so.

5. If you have solid floors, whether there is a damp membrane in-situ would depend on when the floors were installed.

joe-90 said:

Define what you mean by 'breathe'. In the modern world it makes no sense.

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Old buildings made with lime products were meant to breathe. That is, the lime allows the absorption and evaporation of moisture (unlike cement which is impervious). This is how an old building like mine stays dry without a DPC of any sort. I have demonstrated this in the last 18 months from starting with a cold wet heap which is now dry and warm. See my blog http://houseintheenchantedforest.blogspot.co.uk/ and look at the 2010/2011 entries labelled "dampness" and "lime mortar" etc.

hammerit said:

The walls are 600mm thick and appear to be suffering from rising damp, mainly affects the plaster about 300mm up from the floor.

I am not convinced on an injected DPC and would rather 'tank' it from the inside, although all tanking products boast about holding 7bar of water pressure etc.

However i dont have any pressure as such as its rising damp, so i was thinking of sand/cement render with waterproofer in, and then plaster over the top.

Click to expand...

If you want your cottage to be free of damp you must treat it correctly.
1. Do nothing in a hurry that you might regret later; think before doing anything permanent!
2. Do NOT inject a DPC - at best it's a waste of money; at worst you will make the problem worse.
3. Tanking does NOT help; all it does is to drive the moisture elsewhere and you just chase the problem around endlessly.
4. Do NOT use cement, gypsum or any modern waterproofing at all - they will only add to your problems.
5. An old house was designed to work in a completely different way to a modern (cement etc) house. Basically, lime and cement do not mix!

As a priority you must tackle any causes of water ingress such as faulty roof covering, flashings, gutters, downpipes, drains and high ground along walls. My house had all of these faults! Any dead plaster should be removed toether with the nasty cement you will doubtless find on various walls and floors.

When you've done those, let it dry out for months - mine took about four months to start feeling better, and a year to dry completely. Then there's the cement pointing to be considered - I'm now at that stage. This just holds water into the wall because it cracks and the water gets behind but doesn't get out.

I could go on - there's still a disappointing amount of poor understanding about old houses, partly due to those TV programmes where people are encouraged to throw modern materials at an old house. I suggest you google "period property" and "dampness" and look carefully at what you get before you decide on anything.

cheers guys.

no its rendered on the outside, and actually looks quite well from the outside.
I have hacked off the affected plaster on the inside and intend to leave it to dry for a good while!

i suspect it was last plastered in the 70's and it looks as though they've used normal plaster, which obviously hasn't worked.

How would i go with regards to blending in the lime plaster with the 'original' plaster above?

If the "original plaster above" is indeed original, then it will be a sand and lime and horsehair. The render mix that i mentioned above will "blend in".

Mark a meeting line at 1m above FFL, and undercut that line with a utility knife, hack off all below up to the line, and the undercut will give you a clean line to work to.

And if you want it to have absolutely no visible join then you can do the final skim of lime plaster over the entire walls - both the old as well as the new. Mike Wye sell some breathable stuff called DG27 which you can paint on the old plaster to allow the skim to stay attached (see their website).

DG27 is quite expensive but it does work. While I was busy elsewhere the plasterer's mate painted it on the NEW plaster as well, which didn't matter apart from the fact that he was wasting my money!

Breathable means a damp house. That's bad for your health.

joe-90 said:

Breathable means a damp house. That's bad for your health.

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No it doesn't. Every living person and animal creates moisture in a house just by existing, and that's before you start cooking and washing etc. This moisture has to be controlled somehow. A modern house is basically a sealed box made of impermeable materials and so it contains the moisture apart from when someone opens a door or window. Often people forget to ventilate enough and then wonder why they get black mould etc. This is why BRs require window vents, and bathroom extractors etc. In an older house, they were naturally draughty so it was less of an issue, because the lime mortar and plaster did this naturally. Dampness from the ground can come through the floor, into the atmosphere and away- it doesn't remain.

The trouble is that people get excessive moisture due to water ingress from roof/flashing/drainpipe leaks, blocked gutters overflowing, ground outside being higher than floor inside etc, and then try and fix the symptom of dampness instead of addressing the cause.

If you want proof, come and see my house in Oxfordshire - it works as intended and it is now as dry as a bone, simply because I've done what I posted above.

I lived in a house like that when I was a kid. It all depends where the house is situated. If it's on chalk then fine, but if it's on clay you are going to get ill. Ours made us all ill. Neither do people want a draughty house. You don't drive a horse and cart - so don't live in a damp house.