If you have a site that offers building services across the whole country then terms such as window, door and building may, on first glance be what you wish to rank for however you need to consider the following.

If you optimise the site for a term that is too broad such as windows you will be competing with many companies that have nothing to do with your business model, including things such as Microsoft (Windows computer software), window manufactures and so on, so my recommendations would be to target more focused searches such as, window repairs, window fitting.

If you do decide to go for these focused terms you should also look at targeting the local areas for these services, such as window fitters Dorset or window repairs Berkshire.

This is going to be true for all the other terms you suggested, it is going to be better if you target the main term combined with the local area it relates too.

This is because of the way people use the internet, they know that if they just type in window repairs they will then have to filter a lot of worthless sites that are not in the area they live, so they use towns, cities and counties to narrow the search and make it more relevant.

The search engines are also trying to provide as much local search capabilities as they can too, so including the areas is going to help people find you.

This all means that there are a lot more keywords to be ranked for, my recommendation are you select the top 10 areas to target & combine them with the services, see how the results you get for this works out and then add more areas.

We have experience with this sort of thing with companies we do work for, one is an events supplies company that puts you in contact with marquee companies, toilet hire & catering companies all over the country, so they need to be found for terms such as marquee hire Dorset. The other is a restaurants and dining club that review and recommend restaurants, Indian, Italian, Chinese etc all over the North of England, so they need to be found for terms such as Manchester restaurants. You can also do it for terms that offer local services such as web design Salisbury.

This targeting areas for the individual services has proved successful for each of these companies.