Updating Historical Buildings
I suppose this really should go without saying, but before you begin any kind of renovation on a listed building or one in a conservation area, no matter how insignificant it may seem, you really should check with the local planning department or conservation officer, to find out if planning permission is required. The rules on who needs planning permission are slightly more lax than they were ten years ago, but there would be nothing worse than 
doing work and later finding out that it has to be reversed. Changing old sash windows and wooden doors to modern UPVC is a typical example of this.
OK, so with the “disclaimer” out of the way, the first thing you need to consider when renovating an older building is the style you want to adopt, you basically have 2 choices, to keep in with the existing theme and architecture to try to blend in and appear as if it were original, or to have something modern yet complementary. This is generally personal choice, although the former is likely to be far more acceptable to your neighbours and the local planning authority.
It’s always worth engaging an experienced architect, they will not only go through the design and planning stages with you, but also generate drawings which will be submitted for planning consent and from their position of experience be able to negotiate the finer points of the build, sometimes knowing that only very minor changes need be made in order to get your planning approved.
One of the most important things to bear in mind when selecting an architect, is that you get on with them and feel that you can work with them long term. A good place to start looking for someone suitable is the Royal Institute of Architects, you should be able to find someone reasonably local and with the right kind of experience if you do your research. A project will undoubtedly go over budget and take much longer than you expect, after all we’ve all seen Grand Designs on TV, so have at least some idea of the problems one can face along the way, and seen how stressful the whole process can be.
Assuming all goes well and you are able to get on with the build, be it a full extension or just adding new patio doors, you need to decide if you will manage the work yourself using local tradesmen and ordering your own materials, or if you will award the job to a contractor who will manage the whole process for you. Again let’s take the example of fitting new doors, this could involve both a bricklayer and a firm who specialise in installing doors, plus if the opening is being made very wide you could need an RSJ too. Usually this would me handled by a company who specialise and they would do the whole job, someone like the panoramic door company would be able to manage the whole project, and likely come in 
cheaper then if you were going to buy in all the separate materials and services anyway.
If however you are building a full extension the decision is a little more tricky, as if you project manage it yourself, this could give quite a saving, on the time of a project manager, there would be no mark up from a builder on materials and you can negotiate better rates with the tradesmen and keep the difference, whereas a contractor would keep this and mark it up further. Although don’t underestimate the stress involved in doing this yourself, not least in the job of organising the various trades and materials to be on site when you need them.
Just remember that regardless if you are replacing windows, having some top of the range bifolding doors fitted, extending the kitchen or adding a new wing to your stately home (I wish!) make sure you check the local planning regulations and gain the appropriate permissions before you start.
