Radiator shelves

[Srodders]

When putting a shelf above a radiator , is there a minimum height to put it above the radiator? Also what about depth of the shelf compared to the depth of the radiator? Is there some sort of formula where height depnds on depth etc? Any help please, as I would like to put a shelf above our bedroom radiator - mainly to throw heat out a bit further in front of the blind.

Thanks.

 

[gregbbb]

It mentions 10cm here but it seems that is just a guideline. Doubt there is any hard and fast rule.

http://www.housewarming.org.uk/simple_measures/radiators.html

Although, most radiator cabinets suggest 20cm between top of radiator and top of cabinet.

Are you making the shelf yourself or buying one. How are you fixing it?