water seeping bottom of old stone partition wall

21 Jul 2010
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United Kingdom
my house is over 100 years old. old stone walls form a type of out house where i store my oil tank, washing machine and freezer. as my house is mid terrace the old stone walls of my outhouse are party walls shared by my neighbours. problem is, when it is raining water seeps in at ground level from neighbour's side. neighbour is renting the house and the outhouse is not well maintained. there is no point approaching my neighbour about this problem. is there anyway of preventing rain water seeping in through the bottom of the old stone party wall? :rolleyes:
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Does the water run through gaps or just very slowly seep through? I know you said seeps but people have different ideas of what that is so just wanted to check.

Some options in order of increasing cost and hassle would be

1. Chip out the mortar and replace with mortar with added waterproofer.

2. Depending on the size and if you don't mind raising floor level you could lay a new concrete floor and take the DPM on up the walls, though not a good idea if the outhouse is attached to your main dwelling.

Use a full blown tanking product.

What sort of state is the outhouse in? is it watertight with sealed windows and door/ plastered / a floor covering.

If its a rough and ready type structure you could consider installing a little track/ gulley/ linear drain and run the water out the end wall?

Just a few ideas.
If I go out my back door I go down steps and into my outhouse so even though it is attached to the back of my kitchen (old extension) the outhouse floor which is mde of concrete is at a lower level. The side walls which are party walls to the neighbours on both sides are built of old stone but no cement.

The outhouse backs out onto a mews lane and the water seeps in only at ground level along one side but not the whole length of that side. If the rain is fairly heavy the water would run in. your suggestions about putting new mortar between the stones or making a gully sound good. I'm not to sure what is meant by tanking and is it possible to tank old stone walls.

I had my kitchen damp proofed about 8 months ago. The walls were then replastered. I have noticed that in the areas at either side of the radiator the walls sound hollow. any opinions on what this might be? :confused:
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tanking is commonly used in old stone cottages and buildings which have solid walls, also more commonly in basements etc.

I would give the mortar & waterproofer a try as its very easy and cheap. Remember though if you block the water one place it will take the path of least resistance to somewhere else so thought needs to be given if that will direct it towards a party wall or even your own property.

As for the hollow sounding plaster you can be pretty confident it has blown and will need replaced at some stage, It will survive fine though until it gets a good bash and then will start to crack.

Blown plaster is usually caused by damp but in your case it is possible they just didn't let it dry out enough however this is unlikely as they will probably have used waterproofer in the scratch coat. It could also be from a bad mix but that would become obvious very quickly. If they are reputable i would call them and ask them to sort it out.

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