Building a basement: how to keep it dry
I need lots of information on building a basement. I'll take anything from construction, design, good build, bad builds, tanking, damp proofing, companys, as I said, anything. My project is to build an art studio with a basement measuring 30 feet long by 20 feet wide, going down 6 feet to subfloor leaving two feet about ground level for windows and vents.
Thanks Mostyn Powell
Housebuilder's Bible author Mark Brinkley reckons:
The one thing that people really fear, when considering basements, is that they will leak. And it's not a groundless fear. The insurance claims records on new basements is appalling, enough for insurance bodies like the NHBC and Zurich to often specifically exclude basements from their cover. The problem is that relatively minor errors can result in total failure whereas above ground they would most likely pass unnoticed. And of course leaky basements are difficult and costly to fix.
There are basically two techniques for stopping basements leaking: tanking and drainage. Ideally both should be employed. There are several ways of building basements and they are all potentially excellent yet none of them is completely foolproof. You need an appropriate design to start with and you need to employ contractors with above average competence.
One of the problems with basement design is that no one quite knows who to talk to at the outset. If you go to a "basement specialist" they will most likely be trying to sell you their pet system, regardless of whether it is suitable for your site. An architect? Probably won't have a clue. Neither will most structural engineers. An "experienced groundworker?" You may be lucky, you may not, not many UK groundworkers have ever built a basement. You could do worse than check into the Basement Information Centre www.basement.org.uk and key into their database, although it keeps throwing up Phil Hewitt as the only independent consultant email@example.com
One other tip,
Selfbuilder Lol Berman is just completing a new house in Cambs with a 17x8m basement. He costed out four options at the outset:
• ThermoneX £77k (ThermoneX make prefab basement walls, craned into position)
• Beco £56k (Beco are an ICF business, using polystyrene moulds into which concrete is poured)
• Ordinary Local Groundworkers £58k
• David Ball's Pudlo System £41k (Pudlo is a waterproofed poured-in-situ concrete system produced by the David Ball Group www.davidballgroup.com)
He went with the Pudlo system and thus far it's been fine.
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