Laying a Drainage Pipe - Advice Needed

Bluscreendream

Hi guys,

I'm just looking for a bit of advice here, I thought it would be best to post here as I know all lot of folk here would know a lot about land drainage.

I have to lay a drainage pipe parallel to a gable end wall (17') as the floor level inside is lower than my neighbour's garden and dampness from the soil is seeping in through the two leaves of wall. I would be going for the 100mm diameter standard perforated pipe. My question is when I have the drench dug do I have to insert geo-textile (see photos) or can I just put gravel in the bed of the drench insert the pipe and cover it over with gravel?

Thanks for your time

st1979

No you dont. The vast majority of drainage is done with no geotextile layer in field drains. Just pipe and stone as your filter.

J.O. Farmer

I agree that you don't need the geotextile in the field. However your trying to keep dampness out of your house. The reason for the geotextile is to prevent the pores of the land drainage pipe getting clogged and long term that may be more important given it's only 17 foot. In a field you could be looking at 1700 foot.
The thing is though I'm not sure a land drainage pipe will solve your problem. I think you really need to get the soil away from the wall above floor level or do you intend to put the drain tight to the wall.
Also in the drain its clean rough stone you want instead of gravel. Also given it's dampness in the house your trying to solve would it not be better to use a thicker pipe like a 9 inch (sewer pipe size).
The extra cost of erring on the side of caution would be worth it. One final point have you somewhere for the water to flow away to.

severeoversteer

lower the ground outside the wall especially if it is soaking through 2 coarses of blocks, or tank the exterior surface of the walls to prevent moisture penetration but I don't have any faith in this

you should investigate rising the floor of the dwelling, it will never be right if dampness is a problem due to higher ground outside

if the floor to ceiling height allows you should do a job and put in a screed subfloor with insulation and dpm underneath, and you could inject a dampcourse into the blockwork. a dampcourse layer is only effective when 150mm above outside ground level, and your inside floor needs to be above this





I have priced such jobs as this and the other contractor that comes and does a French drain around the house is the best man in the world and the cheapest until a year down the line and the dampness is worse than ever

whereas I would have told the client that there was more substantial work needed and more money need to be spent to get what they want

Bluscreendream

Hi guys, thanks so much for the invaluable advice.

@J.O. Farmer

I think you are right, I suspect a drainage pipe there wouldn't be enough to deal with this issue and that ultimately I need to get the soil away from the exterior wall. I was thinking about it this evening and I came up with a bit of a hair brained idea I've put together a bit of a rough graphic to give you an idea what I have in mind, would ye mind having a look at the two attachments and letting me know if this workable or totally crazy! :rolleyes: cheers

severeoversteer

i have loads of questions to ask you about levels etc but I just thought there that perhaps you should go and buy the ''homebond manual''

http://www.homebond.ie/home_builders/publications1/house_building_manual/

it is €80 plus postage but it will answer all questions, you need to be looking at basement constructional details for your problem

retro work of this type is always unknown whether it will solve it or not

I would still do my best to negotiate with the neighbour about lowering the ground atleast a foot lower than your inside floor.

Bluscreendream

severeoversteer wrote: »

i have loads of questions to ask you about levels etc but I just thought there that perhaps you should go and buy the ''homebond manual''

http://www.homebond.ie/home_builders/publications1/house_building_manual/

it is €80 plus postage but it will answer all questions, you need to be looking at basement constructional details for your problem

retro work of this type is always unknown whether it will solve it or not

I would still do my best to negotiate with the neighbour about lowering the ground atleast a foot lower than your inside floor.

Thanks for the advise Severeoversteer, I have a few books like that. I'm a not a builder and I'm just trying to figure out a practical and affordable way of getting the soil away from the gable end wall.

Oldtree

The homebond book is a mine of information.

Bluscreendream

Oldtree wrote: »

The homebond book is a mine of information.

for 80 quid it would want to be, I'd buy a lot of stock blocks with that money

Oldtree

Bluscreendream wrote: »

for 80 quid it would want to be, I'd buy a lot of stock blocks with that money

for someone in my position that made a lovely flower bed of red brick and then have the cement in between the bricks crack within 2 days, it was invaluable