Manhole

[Mrs Tiggywinkle]

I am in the process of exchanging my old, old free-standing pile for a new, old semi-detached pile.

The new place has no manhole, so I have started off by making a head-sized hole through the added gyprock ceiling, and up through the old plaster and lathe. The dust up there is unbelievable! Even with a shower cap, goggles and mask, it's a pretty unpleasant way to spend a few leisurely hours.

Having burrowed my way into the roof space, I've been a bit surprised to find that the roof timbers are round poles, levelled on the ceiling side. How about that!

So to my query .. the spacing of the ceiling 'poles is around 30cm apart. The manhole in my old place was around 30cm x 60cm. Would that be the minimum dimensions for a manhole, or could I go less than 60cm long, and still have a useable manhole?

[I know it would have been easier to go down from within the roof space, but it would have been a major, major task to have lifted the iron on the very steep roof and I don't do roofs anyway.]

I'm okay to build the manhole frame & cover, once I've got the correct dimensions.

But I also would like to know if there is any additional framing I need to add on the roof cavity side to ensure that it is safe for people to be supporting themselves on whilst hauling themselves up? And it won't be me!

I can put any number of screws through the side of the frame into the pole, but these will obviously have to be in a straight line because of the curve of the poles. Should I make up a top frame to screw to the top of the poles to further secure the box frame?

I'm planning on using MDF for the box part of the frame. Thoughts on this?

Thanks guys.

[Skew ChiDAMN!!]

It sounds like you've taken on a serious undertaking! :oo:

Ideally a manhole would be 60x60 or thereabouts, 45x60 is rather tight and 30x60... well...

But if that's what you have to work with, then that's what you have to work with! Better that than nothing. :wink:

The roof cavity side usually has a frame made up from 70x35 studs/noggins. Two running parallel to each other between the ceiling joists - and defining two sides of the manhole - and the other two nailed perpendicular between them to "finish the box." (Sort of a double-barred 'H' if you know what I mean?)

As this frame sits on top of the ceiling plaster/laths it also gives you something solid to fit architrave on the ceiling side and any internal trim to, so it looks pretty.

Unfortunately your half-rounded joists mean this becomes more... complicated to fit, as the ends of the first two studs will need to arc over the top of the joists. :roll:


Your idea of a screwing a sheet of MDF across the two joists could be made to work, but I'd also screw a couple of studs on top of the sheet, one on each side of the manhole, long enough that their ends span across the tops of the joists. And screwing the MDF to these studs every 150mm or so. It really wouldn't hurt if they were long enough to span four joists!

I know it's only a 30cm span, but when hauling yourself thru such a small gap there's a lot of weight put in a small area, y'know?

[Mrs Tiggywinkle]

Thank you for the advice, SkewChiDAMN.

Because of the small distance between my interesting round ceiling joists, I can't really add any supporting timbers to the inside of the manhole area. I don't have much confidence in finding a 5 year old electrician. (Although from some of the electrical work that has been done in the house, a 10 year old might have done better!)

But I can bolt noggins to the opposite sides of the joists on the sides of the manhole and secure the 'top platform' MDF to that, as well as to the tops of the joists.

I will take your advice and span four joists. There's plenty of head room to haul a long piece up into the roof cavity.

As to the achitrave on the ceiling, I have found that Liquid Nails works a treat for prettying things up.

I might start looking for a thin electrician.

[ian]

"normally" you would cut about 800mm out of one or two of the ceiling joists to make the hole and then frame up the opening so that the free ends of the cut joists were supported by the framing.

commercial roof access ladders come with all the bits needed to frame the opening, though in your case you might need to pack out the inside of two "pole joists" or square up their insides.
(sounds like they maky have used saplings for your celing joists.)

[artme]

Using round poles was a not uncommon building method in many places around Aus., and i suspect elsewhere.

I had an old house on the farm and all the wall studs were poles, flattened on on side with either an axe or an adze. I suspect the studs were put in place with on side plumb and then the othr side was trimmed to suit.

As there as plenty of timber available locally (at the time of building ) ofabout 100 -150 mm diam this was a way to save time and money. Sawmills would have been few and far between. _