Problems may occur where flats have been subdivided, merged, or enlarged into the loft or basement after the title deeds were drawn up. 

Ideally, title deeds for all flats should have been changed to reflect any alterations to flats which occurred after the title deeds were drawn up. If the title deeds have not been changed, then the following guidance may help. In the long term however, you should change the title deeds. 

Where the title deeds say shares are to be divided equally, this is not a problem to calculate. 

Where shares are by Rateable Value (RV), then the title deeds are unusable as there will be no RV for the flat that has had a change in floor area. In this case, refer to what the Tenements Act says about shares. 

Where shares are by percentage or fraction, divide the share for that flat according to what the Tenements Act says. 

To calculate the share each flat owner will pay where the titles say that you need to work with rateable values, do the following: 

1. Find all the RVs
2. Add them all together.
3. Divide the individual RV by the total of all the RVs and then multiply by 100 to get the percentage.

Example 

There are 3 flats and a shop in the tenement. The RVs are: 

Flat 1 – £265 

Flat 2 – £355 

Flat 3 – £244 

Shop – £1354 

Total – £2218 

So for Flat 1, the percentage share is 265/2218*100 = 11.95%. 

If you have RVs for a number of flats to work with, you can download the excel file or set up your own using the formulas shown.