Cumulus Support

Hi

I've been looking through the old posts and thanks to your resourcefulness, I've been building a Stevenson Screen based on Flying Eye's in this thread:-

https://cumulus.hosiene.co.uk/viewtopic.php?f=16&t=6020

I have questions about Stevenson Screen roofs and floor.

Should the floor be ventilated in any way, made of slats or have holes in it? It is currently solid and up tight to the lower edge of the vents

Should the inner roof be ventilated, possibly have holes in it or any gaps say around the edges or even raised slightly? Again it is currently solid and sat on top of the upper edges of the vents.

Also how much larger should the upper roof be? The roof is about 9" square, so was thinking of making it 12" square which would give about 1" extra all round.

So far this has cost less than £20 for the vents and PVC angle, the wood for the roofs and floor I was given

Thanks in advance!

Attached is a guide from the Australian BoM that I used as a guide when I constructed my Stevenson Screen.

As with the base, I have a couple of large holes to provide airflow as most of the pictures I have seen on the net have had open or partially open floor/base.

Gook luck!
Gerard

It seems the floor should be partially open. Often there are slats instead of a floor as such. The inner roof is solid. There doesn't seem to be a necessity for the outer roof to be any bigger than the inner roof. but I guess it will help shade the side vents when the sun is high. The outer roof is often slanted towards the south. Any door is always on the north side.

have fun.

Hi logjam

Thanks for the information. I'll ventilate the floor.

I cut an outer roof over the weekend that was 1/2" larger all round and noticed when fitting it that the sun could shine in between the inner and outer roofs. The back of the outer roof is mounted 1" higher than the inner roof (the front probably 1.5" higher) sloping south and was shining in a fair amount even after moving the outer roof back so it was over the rear of the screen by the full inch. Admittedly it is mounted on a post which is currently higher than the ideal which won't help. I think once at the right height at least an inch all round could be the answer.

I was given this screen many years ago but believe it was made to specification. It has a solid inner roof and an air gap to the outer. The roof is about 30mm bigger all round. The floor has 5 boards alternately above and below a 25mm bearer for ventilation.
The 'door' is hinged at the bottom.

HTH