# Forum Home Renovation Structural Renovation  Manhole size?

## dgp

Is there a legal size that a manhole must be in Victoria?
I am having ducted heating installed and the installer told me i would have to put in a 600*600 manhole. I see that there are a number of different sizes commercially available so i was thinking that there probably is no standard for their size.

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## Moondog55

Personal opinion here >> BUT <<< the bigger the better
we used 750 * 550mm and I wish we had made it 750 * 900mm 
Just remember to insulate the manhole cover; ours is a plywood box; 40mm deep and airtight and using 2 layers of 10mm foilboard inside with another layer of foilboard on top and weighted with some spare plaster sheet under the top layer of foilboard

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## jatt

Have put in 2 in separate houses and as Moondog55 says the bigger the better.  The limiting factor that I found in both was the spacings between the timbers in the roof.  Obviously the less stuffing around here the better.  Remember when lugging something (insulation for instance) up thru the ceiling one can gain considerable girth when fitting thru the hole.  Its no fun getting stuck.Happy hacking.Jatt.

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## r3nov8or

Go an attic ladder if funds and the arrangement of your ceiling joists and other roof timbers allow

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## Black Cat

Yep, an attic ladder would be the best bet if your budget runs to that sort of thing. Definitely err on the large side of things. The manholes in my place - once you put the ladder in, there is no room for the man, let alone any carried objects. Lucky I am skinny is all I can say!

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