How long a basement conversion takes
6 to 12 weeks for most basement conversions, and 6 to 8 weeks for a simple one. The waterproofing is 1 to 2 weeks, then 2 to 3 weeks of finishing. Digging a new basement takes months, not weeks.
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- 6 to 12 weeksmost conversions
- 6 to 8 weeksa simple one
- 1 to 2 weekswaterproofing
- 2 to 3 weeksfinishing after it
A typical conversion
| Stage | Typical time |
|---|---|
| Survey, design and price | Before the start date |
| Strip out and prepare | About a week |
| Waterproofing, drainage and sump | 1 to 2 weeks |
| Radon, insulation and boarding | About a week |
| Electrics, heating and ventilation | About a week, overlapping |
| Plaster, floor and finish | 2 to 3 weeks |
Planning, where it's needed, comes first and takes its own time. A dig-out adds the engineer's design and the underpinning, done one section at a time.
What adds time
- Water coming in all year, which needs drainage and a sump before anything else.
- Rotten timber or poor walls found once the plaster is off.
- New light wells, windows or a stairs.
- Waiting for planning, or a protected structure's consent.
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Basement conversion and waterproofing guides & price breakdowns
Straight answers to what people ask most: itemised costs, specifications, planning or grants, and what to check before you book.
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Questions we get asked
Can I live in the house during a basement conversion?
Usually, yes. The work is below you. Expect dust and noise during the strip-out.
How long does basement waterproofing take?
1 to 2 weeks for the waterproofing itself.
How long does it take to dig out a basement?
Months rather than weeks, because the underpinning goes in short sections and the spoil has to come out by hand or conveyor.
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