In order to quote for interior work i use room size catagories. Bellow is the table that i use. I start by measuring the area of each room. I then place it in a xs, s,m,l,xl category.
I then note whether i`m painting just the walls and ceiling, or also doing the woodwork. This gives me a time in days for the quote i`m preparing. I charge £120/day.
Once i have a rough quote, i then adjust for complicating and simplifying factors. For example, are the ceilings higher than standard so i have to be up ladders a lot, are the surfaces particularly beaten or dirty? Are there stains, cracks, popped plasterboard screws to deal with. Is the property empty, is it unfurnished? Am i sticking to a single colour?
On occassion these adjustments can be significant but more often than not my starting point is not far off my final labour quote.
I then need to work out the cost of paint. Sometimes depending upon the client and the use of the property i offer different paints: a budget and a tougher premium option. Typically this is 10-15% 0f the labour cost.
Finally i include an estimate of material costs. Typically this is 3-5% of the labour quote.
An example would be a 4 meter by 5 metre (13″ x 16″) lounge where i`m painting the ceiling, walls and woodwork. My starting point based on 20m2 is 4 days.
This room happens to be higher, the skirtings larger than typical, and cornices are present which need brushing. These factors would tend to add to the time, but as the room is unfurnished and i`m painting it before the client moves in time will be saved, also, i`m only using white ceiling and two colours of paint for the whole house. Ballance these up and i quote for slightly less than my starting point; 3.5 days. This is £420. I allow £15 for consumables as the walls are clean, the arent any plasterboard tape repairs and the floor dosent need masking with paper. Its part of a whole house refresh so i`m minded to offer a budget as well as my standard premium pant option. This paint is £55 (standard vinyl matt on walls, quick dry satinwood on woodwork, contract matt on ceiling). The harder wearing option paints cost £110 (tough durable matt wall paint, super matt ceiling paint for a flawless and bright finish, extra tough satinwood and undercoat)
This room is therefore quoted at £490 or £545.
It is understood that the quality of the finish and its durability depends on the preperation. Find out more about the preperation i do before i paint.