My extension has been up for some years but I've never got around to installing a soakaway - at present rainwater goes straight into a butt which drains onto the garden via a hose. The council have written saying that I need a soakaway so I'm about to start. I understand that it needs to be a minimum 5m from the building and that the hole should be a minimum 1m3 but I'm not too sure about the pipe depth - does this need to be a minimum depth under the patio/decking ? If the soakaway is 5m from the house and the pipe enters it halfway down (0.5m), incorporating a fall in the pipe, I can see that it will be quite near the surface at the house end ?? I have looked at the pavingexpert site and am not much the wiser so if anyone can give me any hints or tips I would be most grateful.
My personal view is that soakaways are next to useless unless in well drained sandy soil. If you think about it, if you dig a hole for a soakaway it'll probably fill with rain up to the water table, which may not be more than a few inches below ground level. How can this hole, when then filled with broken brick, possible suddenly turn into a useful receptacle for rain water?
Has the council indicated that it will inspect the soakaway during or after construction?
Exactly my way of thinking :( The inspector said he would need to inspect it during the process - I'm part way through digging the hole - just need some guidance to put my mind at rest. Cheers, Franko.
Clay unfortunately - most of it stuck to the bottom of my feet at the moment, I also forgot how knackering digging was . . . . and the amount of space almost 1m3 of dug soil takes up - puff, pant :(
As I understand it it soakaways should be roof area x 50mm. This will give you the volume of void space you need. If you fill it up with bricks then you are reducing the void. Also you should use 110mm pipe as this will have some storage capacity. Keep digging!
Cheers Mark, I've hit water less than 1m down and struggling. I have been looking at the soakaway modules at
formatting link
and am now thinking of maybe going this route as it seems that the rubble filled drain will not last that many years before maintenance is needed and SWMBO would not be happy with me needing to dig up the lawn again. The main problem I have at the moment is the water table. Cheers, Franko.
The problem is - and I hate to be negative - but I think you're probably wasting your time. Is there any possibility that you could take the water by means of a land drain to some ditch or other?
Ask the building inspector if, were he to require a fireguard for some part of your house, would a chocolate one do?
Cheers Rob, I don't think you're being negative at all - I'm thinking exactly the same thing, unfortunately I don't have the luxury of a ditch within 1.5 miles of here. Got a lovely sewer that could probably do with a flush of fresh water now & then to clean the 'cobwebs' but they don't allow that around here. I live in an area that was used for brickmaking in times past - I can see why!! There are loads of extensions in this area so I imagine the inspectors aren't really that fussy as long as they see a hole with a few bricks thrown in, I'd just like to do it properly. Pile is getting bigger with wet clay - do you think I should stop until I get the inspector around?
If you're 900mm down you shouldn't dig much deeper without supporting the excavation. Any deeper than 1.2m is asking for trouble, of the life ending kind. It's OK if you're out of the way in an excavators cab, but you're hand digging in the hole itself from what you've written so far, be careful out there!!
If you think I'm being over protective....go here.
I had a look at the publication mentioned and I am surpised that with all that detail there is no mention of overhead services. Excavators, cranes and forklifts often hit them in my experience. Robbie
Robbie, My day job is a Civil Engineer, mostly highway structures. Bridges, retaining walls, culverts, headwalls etc. You get the picture. The advice I was trying to give was specifically about excavation collapse safety, bearing in mind the OP mentioned his hole was three foot (900mm) deep already and he was hand digging. I was concerned that he may not fully appreciate how dangerous excavations can be. Next time you're on the beach lie down in a 12 inch deep trench in the sand and get your kids to bury you in it with the sand removed to create it. Now stand up, you'll just about do it if you're rough and tough... but only just!!
The publication concerned is an HSE (Health and Safety Executive) publication and is specifically aimed at the safety of excavations WRT collapse. You are absolutely right in saying that overhead cables are a hazard, but this would be a different area and the publication I referred to is not trying to address that. Indeed there are other hazards to think about when excavating but trying to get all of those messages over in one publication is going to dilute the message.
I would agree that if the OP decided to bring in mechanical plant there are a whole host of other risks he should be addressing including overhead plant. As an aside buried plant is far more likely to be a problem to the OP if he doesn't take care, even with hand digging old electricity cables can be cut, and 240v up your shovel will probably kill you and at the very least do you considerable harm.
As for plant and machinery often hitting OH plant, I've been in this game over 20 years now, large and small schemes (£10,000 to£12,000,000) and in my experience hitting overhead plant is a rare event that should rightly end in someone being sacked, (and I don't mean the driver necessarily) You can see the stuff overhead, no excuses = zero tolerance. The uncharted stuff below ground can be more difficult to avoid. Especially if the waterboard/gasboard use plastic mains, don't put a tracer wire on the pipe and don't really know where they put it...this seems to be common practice in the UK!
In some areas of Calafornia, if you want to dig a hole, you call a single free number. All utilities are notified and come and spray paint where their ducts/pipe/cables/etc are. This is a free service, because it works out much cheaper for the utilities than having their property damaged, and resulting loss of service. If you then damage one which wasn't marked, the utility foots the bill for fixing it. If you damage one which was marked, you foot the bill.
In the UK too, more and more at design stage we use single companies to do the NRSWA (new roads and street works) enquiries. It's easier than wasting a designers time chasing 20 odd utility companies. Ultimately it's still up to the contractor to find out where the "stats" are. Use of cable locators and trial holes means striking underground plant is not common, but still more common than the overhead stuff.
Update: Dug down to 1200mm plus tried a sump in one corner a foot deeper - the hole filled up with about 2 feet of water within 10 mins of baling out, time after time. Building inspector visited during the week and didn't really know what to say - I got the impression that he would agree to whatever I decided to do, then asked why I hadn't thought of using the foul drain which is five feet from the extension !! Anyway - looked at my water bill and noticed that I am being charged for surface water drainage, I phoned Southern Water this morning and asked if it would be ok for me to channel rainwater into the foul drain, she said "fine, no problem". This is the direct opposite to what the building inspector said as I was putting up the extension as he told me there was no way I could use the foul drain for surface water and MUST have a soakaway. Note to self: Double check with water company before digging huge hole in lawn next time :( Now to fill up the big one and dig a much more reasonable one :) Many thanks for all your input, Franko.
That doesn't mean it won't work as a soakaway. If you fill it a foot higher with water, it will still drop back down to 2 feet deep, or whatever the water table is that day.
A friend did this a few years ago. He needed it in writing to give to the BCO though, or it wouldn't get signed off.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.