We also do all types of work. if your looking at going into different types of cleaning the best thing to do is work out how much money you've got to spend for a start. You have basic set ups for pressure washing for about £1500 (2nd hand), £1000 - £2000 for carpet cleaning depending on which equipment you use, builders cleans need less investment but you may need to spent a bit of time trying to get the work. The next thing is to work out how fast you want it to pay itself back, pressure washing is quite quick but the more you make you'll want to spent it on a boiler to get steam, new lances, or another machine for bigger jobs. Domestic pressure washing tends to be spring summer time but commercial can be all year. Carpet cleaning can be throughout the year but doesn't have as faster return on investment as pressure washing.
If you can get regular builders cleans that pay on time and a good wage it can keep money coming in if other work dies down abit.