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  • Bliss Interiors

Top tips when extending an old building

Updated: Mar 16, 2020

Many houses in our area of Surrey date from the 19th Century and often much older, and while it’s very possible to build beautiful extensions and additions to older buildings, there are some key points you need to consider to get the best results…


Structural safety

Ensure the services of a structural engineer when doing anything remotely structural, from knocking down an internal wall to building a single storey kitchen extension.

Planning:Always get professional planning advice. This is particularly important if you are in a conservation area or if your house is heritage listed or a listed building. These sorts of buildings carry additional constraints in terms of what you can and cannot do regarding any renovations or building work.


Older properties inevitably let in the cold. This may be through the roof, the windows or through lack of cavity structure. Before doing any new works, consider the best way to insulate the existing building as well as the new addition; be it adding secondary or double glazing (there are sympathetic options these days), checking the loft for a good covering of insulation etc.


Many old buildings do not have a damp-proof course. Consult with your surveyor, engineer or builder on how best to damp-proof the existing structure – particularly in the area directly adjacent to any new addition.

Loft conversions

Converting a loft is a very popular method of increasing space in older buildings that often have quite generous roof space. The rule of thumb for attic / loft conversions is to allow for a minimum of 2.1 metres headroom at the top of the intended staircase. Don't forget the extra level of floor and new ceiling in this measurement. NB: floor thickness to total around 280 mm and add 100 mm to the underside of the roof timbers.

Be sympathetic

Consider closely the aesthetic elements of the original building; e.g. types of windows (lattice, casement, sash), decorative roof fascia or quoins (decorative features round windows and corners of a house), brick patterns or tiles and make sure these are sympathetically reflected in the new build.

Line and Form

Keep the extension subservient to the original line and form of the house. It's easier to get planning permission that way (or could even be within permitted development) and it looks much better - keeping the character of the older building at the forefront.

Reuse and reclaim!

Make sure you scout out the local reclamation yards for materials such as tiles, stone and bricks that will match your existing home. You can also find all sorts of architectural and decorative salvage that will not only be sympathetic to your original home, but could also save you money.

If you’re thinking about renovating, reforming or extending your home, whatever its age, feel free to give us a call.

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