Basement garage tanking?

[the snooper]

Here indoors was a farmers daughter & lived in an OLD farm house, when we got married the one thing she insisted on was we NEVER bought an old house After 47 years I think!! I never have.
But if you tank especially on a hill why cant you build in a drainage system & tank over it ?

you can do that, that is why some have a sump built in and an automatic pump which will cut in when the water builds up

 

[dannyp]

pulling water out of the ground that houses are built ontop of can be risky. problem is if it has allways been wet and you suddely dry it all out things can move or erode.

worst cas i've ever personaly seen was a simalar thing house on hill with a very wet cellar, owner of the house got someone to dig a large sump in the cellar. that consisted of a brick built rectangel with the motar missing in all the vertical joints on the lower courses about 1mtr by 2 mtrs and aproxamtly 5 foot deep. on the inside the base sloped towards a 6" pipe that exited on the one edge that went out under house wall and ran about 50 meters to a ditch, around this was filled with gravel. floor was then concreted but leaving an accses hatch.

apparently this worked brilliantly for years and there was quite a reasonable flow from the outlet the house was dry and all was good. but in the last few years they had noticed that it was flowing faster about the same time a few cracks were appearign in the house.

we were asked to price up putting these minor things right and adding an extension, we both had a funny feeling about it so had a really good poke round and ran a mile.

problem was in that area the water tabelis very high and there are a lot of springs as you drain water out more just pops up to take it's place but sometimes carrys a bit of mud/sand/ silt with it as it dose it makes it easyer for more water to follow so it follows faster and can carry a bit more. over the years this drain had moved quite a lot material away from under the house hence the house was creeping down as the ground setteld down.

 

[brightspark]

unless theres a stream running under your house just tank the walls and floor any water will just go round or underneath as it has for years i hardly think it was running across the floor previously

 

[dannyp]

why id rather tank than drain.



that was a very extreem example but sometimes people create streams without realiseing it.

 

[500e]

Was thinking a small pipe at floor level to drain excess out of building behind tanking not a full blown sump pump

 

[mike os]

I would suggest a cementitious tanking compound. .... fil) cavity etc to give a flattish surface and paint on 2 or 3 coats

most are semi pervious so allow the structure to breath a little

 

[bigdry]

This might explain what i mean a bit better

http://www.buildingconservation.com/articles/damp/damp_cellars.htm

In short,our old house(in croydon i might add not on a mountain) had flint with old lime mortar foundations although the so called basement was about 4' deep i wanted to store stuff down there,my idea was the same as the OP tank it out.
But as i inquired about this i was told NO,the so called cellars in the row of houses were built like this to act as a soak away from water build up,if i did tank it no matter what way i would get a build up of water/moisture outside this,thus causing rising damp further up mine or next doors walls etc.
Same thing could be said for the OP house,his cellar may act as a soak away from the main house

Many thanks for that. Unfortunately the only other people there that have basements seem to be old people with no interest in "repairing" a damp basement that has always been damp since it was built . the attitude is just that , its fine and supposed to be that way! Im coming round to your way of thinking , think i will repair the obvious holes and really poor parts with cement just like it was built originally. i might then spray with the local emulsion paint they have there (actually made in factory near by , just along from local cement factory...) that way it will clean up and brighten the surface (just bare cement at mo) and hopefully tie the surface in a bit so that it doesn't crumble as much when brushing past, sweeping off cobwebs etc, but hopefully let it breathe as needed.
I can let tanking be a last resort if it doesn't get any better.

I think some ventilation will help too, thinking of putting a positive pressure air fan into the building and then using an old flue that rises up from the basement (used to be a wood burner in there) as an exit vent. What do you all reckon? Possible a spinning metal turbine chimney vent on top of the chimney to help extract the damp air?