My observatory has no roof

[JamesF]

Looking at the patent referenced from the hurricane house web page referenced above, I was struck by the realisation that people have been creating roof ridges in a similar fashion for hundreds of years using ridge tiles with a vertical extension.  I'd always assumed these were purely decorative, but I now find myself wondering if they weren't also aware that such ridges could prevent damage to the roof even if they didn't know why.  For example look at the ridge tiles here:

http://www.bricksandbrass.co.uk/design_by_element/roof/victorian_and_edwardian_ridge_tiles.php

or do an image search for "crested roof tiles".

Somehow I think the patent holder might have an exceptionally difficult time enforcing it in the face of so much "prior art".

James

[itmo]

it's an US patent. So prior art is not a problem until someone sues to overturn the patent.Some lady just patented a finnish baseball signal fan there..70 years of prior art on that.   

[SnakeyJ]

Looking at the patent referenced from the hurricane house web page referenced above, I was struck by the realisation that people have been creating roof ridges in a similar fashion for hundreds of years using ridge tiles with a vertical extension.  I'd always assumed these were purely decorative, but I now find myself wondering if they weren't also aware that such ridges could prevent damage to the roof even if they didn't know why.  For example look at the ridge tiles here:

http://www.bricksandbrass.co.uk/design_by_element/roof/victorian_and_edwardian_ridge_tiles.php

or do an image search for "crested roof tiles".

Somehow I think the patent holder might have an exceptionally difficult time enforcing it in the face of so much "prior art".

James

Good point James - we are standing on the shoulders of our Fathers and Grandfathers and probably should have done some more listening in our youth

I particularly like RT16 double 6 point star ridge crest, sure I could re-create this in timber and get a decorative feature.

[r3i]

Seems sensible r3i, how have you attached the straps to the bottom of the obsy ?

It just runs under the decking joists - it's a single piece of strapping so basically works like a trouser belt.  When it's not windy I just roll them up and tuck them under the decking.

[astronymonkey]

From the graphs on the hurrihouse website it seems the greatest lift comes with a gable roof at 15degrees and this is double the lift seen at 25 degrees. Unfortunately 15 degrees seems like the pitch on sharkmellys roof which may have meant it was going to experience a lot of lift in highmwinds.

despite the sad loss of sharks roof we may all have learned a little bit about how critical roof slope angle is for high wind survival.

Cheers

[Gina]

15 degrees is a very common angle for apex roofs.  I think mine's a bit less - I forget.

[sharkmelley]

Gina - I've just seen the pictures of your roof on the ground.  I'm glad you were able to repair it.

Here's another picture of mine, to put in the context of the shed:

Mark

[RikM]

Gina - I've just seen the pictures of your roof on the ground.  I'm glad you were able to repair it.

Here's another picture of mine, to put in the context of the shed:

obsy_roof5.jpg

Mark

Seeing it this way Mark, it looks like it was blown along the runners and off the end stops, rather than 'lifted' off?

[sharkmelley]

The roof had been ripped upwards splintering its supports and then probably propelled backwards along the runners.

Mark

[Gina]

Amazing! and what a dreadful mess   I feel for you.

[Macavity]

Thinking of buying myself one of those low-profile battery digital kitchen / postal scales (anyway).

http://www.ebay.co.uk/itm/10KG-DIGITAL-ELECTRONIC-KITCHEN-POSTAL-SCALE-POSTAGE-PARCEL-WEIGHING-SCALE-/380746695960?pt=UK_Kitchen_Accessories&hash=item58a6458518

A cheap one? Stick a "foot-square" (whatever) thin sheet of wood or metal to it.

Measure the actual (live!) wind pressure (positive of negative!) for myself...

Far more interesting usage... After a surfeit of posting and cooking?

[jnb]

After reading all that I'm sitting here calculating how much Mrs JB' s studio weighs. I'm about 1000km away from it at the moment and it's on an exposed field edge in Sussex.

[Zakalwe]

My solution:

Four of these bolted down with the pier fixing studs. The roof will have to come apart, or the ratchet straps fail or the 12mm studding will have to strip their threads before it takes off.

[itmo]

One option could also be to setup a fence on the wind side of the building to lift the airstream clear of the building. Or bushes or something. anything to make sure the "clean" airstream doesnt hit the building, instead make it dirty with bushes or direct it over the building. 

[stephen_usher]

One option could also be to setup a fence on the wind side of the building to lift the airstream clear of the building. Or bushes or something. anything to make sure the "clean" airstream doesnt hit the building, instead make it dirty with bushes or direct it over the building.

Maybe this will give you some ideas for a windbreak?

http://www.agriculture.gov.sk.ca/Default.aspx?DN=adb8ecee-7d31-4f72-8d83-c71ac97baba4

[stephen_usher]

My observatory's thankfully sheltered by a fence, the house and other buildings in the area. Even so Nick from Alexander's Observatories used a padlock loop and bracket on each corner of the 6'x6' roof to lock it down.

The observatory itself is only bolted down by the ends of the runner supports, but I've never seen it move (other than when I've shifted it with a sledge hammer).

[astronymonkey]

Maybe this will give you some ideas for a windbreak?http://www.agriculture.gov.sk.ca/Default.aspx?DN=adb8ecee-7d31-4f72-8d83-c71ac97baba4

this is a good article and suggests the best protection is with 33% porosity , so gaps between the planks, and this gives protection away from the fence off about 8-10 fence heights. Im amazed though at a reduction to 15 -25% of the original windspeed within this ptotected zone.

Im wondering if a mini picket fence , with 33% porosity, along the front edge of the roof, similar to those you see on some pigeon lofts, would provide the necessary windspeed reduction on the roof to prevent lift. So an 12 inch front fence could protect a 8-10 ft roof .

interesting stuff and a simple measure to retrofit.

cheers

[r3i]

Four of these bolted down with the pier fixing studs. The roof will have to come apart, or the ratchet straps fail or the 12mm studding will have to strip their threads before it takes off.

 ...or it'll take half the planet with it across your garden

[yesyes]

or the pier foundation might move...

[Zakalwe]

or the pier foundation might move...

Yes, it might. If that happens though, then I reckon there's not much I could have done. There's a cubic metre of concrete in the pier base with rebar driven into the ground. If it moves that then I think that I will probably have lost the roof off the house by that stage!

[Mr TamiyaCowboy]

glad to hear everything is drying out mark and fingers crossed all is good when powered up. 

your new image does show how your roofing left the building,  Uplift was created on the hangovers.

not much was needed before the roof rolled back a slither enough to allow wind to grip.

then on it was up and over it ran along the runners and tree wards. nothing you could have done

just nature showing us who is boss. 

breaking up windflow with bushes and shrubs does work well, but we want clear skys around the obs so

they tend to be placed remotely on thier own. so maybe the wifey could have a few bushes placed in the garden

near your man cave. ( maybe a budding topairy telescope could be carved from said shrubs/bushes)

Be careful mounting the tiedown rings to the pier itself , problem is it is central your needing to tie down the corners

when you use the pier if the roof is lifted it still has a chance to swing around being being fixed down at a central point and not the four corners.

think of a parachute on a drag car single rope to the chute when deployed it spins and flops around same could be for a roof tied down centrally.

you have to be sure those runners will not allow sheer movement of the roof , if the wind gets inside the lifts going to become bigger with pressure differences. 

[Zakalwe]

glad to hear everything is drying out mark and fingers crossed all is good when powered up. 

Be careful mounting the tiedown rings to the pier itself , problem is it is central your needing to tie down the corners

when you use the pier if the roof is lifted it still has a chance to swing around being being fixed down at a central point and not the four corners.

think of a parachute on a drag car single rope to the chute when deployed it spins and flops around same could be for a roof tied down centrally.

There's 4 x  ratchet straps running to each corner of the roof.

[Mr TamiyaCowboy]

There's 4 x  ratchet straps running to each corner of the roof.

missed that bit lol 

yep, just make sure the runners are secured good to for sheer. 

dont have to have these inside, you could strap down around the external.

its more hassle having to walk around and unclip the roof but it allows you to check the ob

each time and notice defects repairs as they happen.

we got some more wind and rain on the way, gusts to 70mph ( take it with salt ) and rain,

should pass fairly quick but you cannot say. stay safe everyone and locked down

[itmo]

Incidentally , my obsy has no roof either nor walls 

[twintin]

I have my roof secured using heavy duty hasp and staples. I fixed one at each corner inside the obs mounted vertically so when pushed together I just drop a large bolt through the eye. This completely stops all movement and is very secure, it only takes a few seconds to pull the bolts and undo the roof.