Planning a Basement Dig

Planning a Basement Digfeatured

We are those awful people – the neighbours who have decided to dig a basement under their house. I know, it’s dreadful in some respects, but with a growing family comes a need for more space and the stamp duty changes have made moving house prohibitively pricey. So in November, we handed over the keys to a specialist basement company.

Digging a basement beneath your house is one of the biggest, most disruptive and most expensive home improvements you can do. It’s theoretically possible to stay living in the house while the work is done, but with the amount of dust being generated daily, I wouldn’t recommend it – especially if you have young children

There’s a lot to do before you even begin the dig. And we mummies are often best placed to make sure that it all gets done.  If you’re planning on doing a basement, here’s my list of some of the key initial considerations:

1. Architect. Use an architect with strong links to the Council. With press articles of houses collapsing into basements, and high profile complaints from neighbours to so-called ‘iceberg’ houses, councils are taking an increasingly dim view of some basement developments. Your architect should know the area you live in well, understand the latest rules and guidelines, and ideally have a good professional relationship with Planning. You could either take a drive round the local area (often the name of the architect is put on the hoarding), or look at the latest successful planning submissions on the Council’s website. Also, make sure your architect is RIBA qualified. How much you rely on your architect is up to you. At one end of the spectrum, they can do the drawings and stop there. Alternatively, you can opt for your architect to be fully involved and managing the project throughout. However, if you have a reputable contractor with a strong management team this may not be necessary, provided you’re fully involved in the project too (as oversight is required) – this can save a considerable amount of money, but you do need to stay on top of things.

2. Structural  Engineer. Ensuring your lovely house doesn’t disappear into a hole is all down to the calculations of the structural engineer. Her numbers will be the maths holding up the whole structure. Again, make sure your engineer has experience of basements. In order to run the numbers, the engineer will generally ask for the results of an exploratory dig to test the soil under the property. She will provide a method statement (ie a description to the Council of how the works will be carried out) to be submitted as part of your planning application. They will need to provide your architect with comprehensive calculations in order for the architect to complete the detailed specification drawings you’ll need in the tender process (see 3 below).

3. Comprehensive tendering. Ask your architect to draw up a detailed build specification itemising on a line-by-line basis the things the builders will be required to do. Assuming your architect has decent experience with basements, they should be able to prepare a pretty comprehensive list, but do check this to make sure they’ve understood your exact requirements and that nothing is missing (or you’re asking for things you don’t actually want). This spreadsheet can then be sent to contractors as part of your tender process. As it will detail every item, it will be easy to compare prices from each contractor. It will also make it easier throughout the dig process to limit the number of “extras” if the spec. is as thorough as possible.

4. Budget. There’s no denying it, basements are spenny. In fact the sky’s the limit when it comes to price. A single level dig beneath a standard London semi can stand you in at between £300 – £450k, and that’s before the fit out. So budgeting properly is critical: the last thing you want to do is run out of cash mid-project. The good news is that interest rates are very low at the minute and banks are still offering amazing fixes. In order to budget properly, you need to run a comprehensive tendering process (see above). Keep half an eye on things you may not have included, eg specific finish items like bathroom fixtures and fittings, wood flooring, carpentry, audio visual etc. Also, be aware that your neighbours may ask you to  put money in escrow (ie in an account with a third party) in case you fail to complete the works or there’s a major problem. While technically not lost, you should get it back at the end of the build, this can be a hefty amount of cash out during the course of the project.

5. Party Wall. There ain’t no party when it comes to a party wall, and basements can be divisive – neighbourly forbearance cannot be guaranteed and quite rightly if there are cracks or any damage to your neighbour’s property, it’s up to you to address this swiftly. Take care when picking a party wall surveyor, it’s a quasi-judicial appointment and so once you’ve appointed one, it’s practically impossible to get rid of them – even if they’re totally incompetent. You are of course responsible not only for your own surveyor’s fees, but also those of your neighbours (who thus have no incentive to keep costs down). Try if you can to have all parties represented by the same surveyor – technically the surveyor’s client is the wall itself, so there shouldn’t be a conflict. The best way to engineer this is by asking the neighbours whether they’re happy to use your surveyor and if they say no, let them appoint one and ask whether she will also act for you. Again, having a single surveyor will save you money.

The above is just the beginning, and there’s a fair bit to think about. If you have the time to grapple with all of this yourself, it should be a cheaper and ultimately more rewarding process. The build itself requires less input than these preliminaries (we meet our contractors once a week), but it’s worth taking the time to get it right.

I’ll be reporting back over the next few months how the dig itself is going and the lessons I’ve learned.

If you’re thinking of digging a basement, do get in touch if you have any queries, and if you have friends who might be interested, please forward or share.

Love Mummy B



About the author

Mummy Bisson

Welcome to Mummy Bisson – a personal journal of everything we do as a little family and the wonderful things that inspire me as a Mummy. On these pages I will share with you the best bits of my life with two little lovelies – the laughs, the love and the little things that make it special. Thank you for coming to my site. I hope you like it and do please share with your family and friends!

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