Building black holes

Rotten Timber
Another common area for extra costs is rotten or bug-infested timber, particularly in older properties. When you expose the joists you will quite often find some of them rotten, normally on the ground floor. This is not a major problem compared to timber infestation which could affect the entire structure of the property. Again you will not know until you hack off the plaster and lift up the floorings.

Plaster
The 'wet trade' of plastering is very skilled, very messy and can be quite expensive. Determining the nature of your plaster on your newly-bought Victorian home is a perilous business. You will only gauge its full condition once you have stripped off the many layers of tasteful wallpaper. In the best case scenario, holes can be bonded and filled, but in the worst-case scenario whole chunks of plaster accompany the paper from the walls. It is worth getting an idea of re-plastering costs even if it turns out not to the necessary.

Chimneys
Gas fires are very much in vogue these days but rightly require proper testing to ensure adequate ventilation. A common problem is that your chimney fails a smoke test so you have do drop a stainless steel flue down the chimney to ensure that no gas can escape into any upstairs flat or rooms. This will usually mean scaffolding is required but that may not be the end of problem. It is also common for the bricks of the chimney stack to collapse in on one another at some point in the chimney. This can mean opening up the chimney breast at various locations, some of which may be in your neighbour's flat above.

The party wall
One of the major stumbling blocks to a renovation project can be your neighbours. It is normally much worse if you are planning the works at the time that you are buying rather than planning changes to your existing property because your neighbours are more suspicious of you before you move in. The party wall act dictates that if you are doing any structural work which involves the party wall (the shared wall between you and your neighbour) you need to get a party wall agreement. This typically takes a minimum of two months. It can either be a written agreement between neighbours or involves a formal inspection by a party wall surveyor. The bad news is that your neighbours can insist on using a different surveyor than you do, which essentially means paying for the same work twice.

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Felix Milns is a journalist, property developer and building contractor. His company, Zulufish Ltd, specialises in design-led refurbishment, extensions and conversions in west and south west London. For more information contact Felix@zulufish.co.uk.