Ah apologies. Does there tend to be a lot of variation between a 4m and 5m width carpet? Are you saying you’d do them all in one length to ensure that doesn’t happen?
I added 10cm on each measurement for the cuts but assume you mean something different? My method was to take the shortest length as other than the loft each room is less than 4m and thus the offcuts would do most of the stairs.
I’ve already explained in two seperate posts the basics of measuring, planning and how carpet is supplied. I’ve also detailed what you have to take into consideration when planning an installation, trying to explain how to measure stair cases correctly is a lot more difficult to explain, especially as in your case you have a bullnose and a number of winders that are all individual sizes and split over two stair cases.
You say you need 65m2 of carpet, I’ve been in the trade 30 years and am suggesting you need closer to 80m2
Again, the basics, you’ll need some graph paper so you can draw out your room sizes and landings and your stair pieces to plan best use of the carpet that you have to plan from 4 or 5m wide widths. You basically mark out 4m wide and then a long length that represents the carpet roll you order from and draw your room sizes and landings and stairs onto it to work out how much carpet you need.
All the computerised estimating software packages I have been shown essentially require you to do exactly the same but electronically, they do not work the carpet plan out for you.
Carpet has to be purchased in 4 or 5m wide rolls.
A 4m Roll and a 5m Roll of the same range and colour WILL NOT COLOUR MATCH.
So you are better off planning ALL areas from either 4 or 5m wide rolls, not a combination of both unless you don’t mind colour discrepancy.
Carpets have a pile direction. If you cross pile direction between carpets in adjoining areas, then even if you have ordered all carpet from the same roll/width, they will appear a different shade due to the way the light reflects off the pile at different angles. In the adjoining areas.
Carpets should be planned fo have the pile lay over the nosing of a stair and/or Landing. Running the pile accross the stair will cause premature wear and likely be hard to fit and getting a good finish would be hard/impossible as the carpet won’t bend over the nose properly and the pile will lay incorrectly.
You can’t order carpet in the sizes that you have listed.
For example, a room 2.50m long x 3m wide would have to be ordered from a carpet 2.60m long x 4m wide which obviously generates wastage that you have to pay for unless you can perhaps use the 2,60 x 0.90m off cut for some stairs.
Each bullnose and winder step has to come from an individual piece of carpet planned from a ‘cutting plan’ or off the side of a room piece.
Straight stairs can be planned in ‘runs’ or as individual stairs depending on the most economical way of planning from wastage or a piece of carpet but ALWAYS needs to be planned so the pile is running correctly and preferably from the same width of carpet as all the other areas of the installation.
Carpets can be joined (known as heat seamed in the trade) however again, the waste to add onto a piece to be seamed together should come from the same width of carpet and lay in the same pile direction otherwise the seam piece will look a different colour to the rest of the installation.
The above refers to plain and plain loop pile carpets, if you are planning a striped carpet or a patterned carpet, you will need to allow for the pattern repeat across the width and on the length (if there is one on the length) to allow enough material for the fitter to line the design up correctly.