Observatory has no roof!!!

[MarkS]

I put a temporary roof on it Boxing Day morning by salvaging what I could:



It survived last night's storm but the tarpaulin leaked so the floor was a bit damp (it hasn't had a chance to dry out yet).  Bought a heavy duty tarp at 7:30 this morning from Jewson.  Once the gusts have dies down a bit, I'll put it in place then I should be weatherproof again.  Looks like the inside of the shed will recover.  Electrics are fine so I've got a fan heater running in there now and already dry patches are appearing on the floor!

[RobertM]

Not withstanding the roof, it's good that the fabric of the building is still sound and that there appears to be no other lasting damage.

What about the equipment - mounts, telescopes and the beer fridge ?

Robert

[mickw]

Did someone say Beer ? 

It's good that you managed to get it covered in quickly with last nights episode - the forecast for Monday/Tuesday is looking dire as well

[Carole]

Well done Mark, I was wondering how you were managing during subsequent bad weather. 

the forecast for Monday/Tuesday is looking dire as well

It seems unending.

Carole

[MarkS]

I'm pretty sure all the equipment will be fine - I'm giving it all time to dry out thoroughly.  Scopes are all definitely OK - the C11 has dried out.  The good quality tarpaulin is in situ now so it's weatherproof again.  Fan heater is drying out the inside.  Haven't tested the beer fridge yet.

It's pretty clear to me now that the roof lifted up because it acted in the same way as an aircraft wing, generating lift as the air passed over it.  So why on earth would anybody do this:

http://en.wikipedia.org/wiki/747_Wing_House



Someone on SGL pointed out that a vertical obstruction along the ridge of the roof disrupts the airflow thus preventing the lifting and that maybe that is why older houses have ridged roof tiles like this:

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

[MarkH]

So why on earth would anybody do this:

Bloody architects Mark ... ever tried shifting furniture up staircases? And what about the architect that designed that idiotic building in London shaped as a parbola, that set shops opposite alight , you'd have thought architectes would have a grasp of basic physics, obviously not 

[mickw]

Wickes do something that might do the trick - probably other suppliers also.
http://www.wickes.co.uk/invt/240040

It should also be flexible enough to "tweak" with a hot air gun

[MarkS]

Another pic that puts the roof and shed in context:

[RobertM]

Looking at the roofs final resting place, are you sure it wasn't just pushed back on the rollers by the force of the wind ?

[Les R]

Yes it does look like its just been pushed off the end of the runners . It it had been lifted in the closed position, I would have expected it to comletely flip over altogether.

[MarkS]

The pattern of damage can only be explained by the roof lifting up sufficiently to rip itself free of the cross-members holding it down (which are still padlocked in place on both sides) and then sliding back along the runners until it crashed into (and destroyed) the back stop and then crashed into the ground with some considerable momentum.

Here is a picture of one of the 3"x2" members which was snapped in half by the force of the roof lifting up:



The tarpaulin seems to have held during the storms whilst I was away in Spain from the day after Boxing Day until the New Year.  I haven't looked inside the obsy yet because the weather is too horrible and we've only just had power restored after another 2 hour power cut

[Mike]

Wow, that was some force to do that. I agree with your previous statements that some kind of ridge or set of ridges along the roof to prevent a low pressure airflow would probably have prevented this as it has clearly acted like an aircraft wing. Alternatively when you rebuild why not put a flat roof on it ?

[MarkH]

Mark your last photo put into context a bit more of what happened. I think the negative pressure caused by the wing effect has lifted the roof enough to allow the wind to get up underneath the gable and do the rest. I recon your original design would have survived if  you'd had a deflector comming out from the wall immediately below the edge of the rooof and extending up covering the verticle face of the gable. Testament to your wood butchery that the roof pretty much stayed in one piece.

[MarkH]

On the plus side I don't think you could have ever foresaw what had happened, and at least you hadn't shelled out on the nice William Morris wallpaper and at least the hand towell dispenser survived

[MarkS]

Just been inside the observatory to check for damage during my time away.  Most of the floor is completely dry but in a few places drips have been getting in through the temporary roof because of a (at least one) hole in the tarpaulin caused by chaffing.  I've put some buckets inside to catch drips.

It's quite scary being inside because of the racket the tarpaulin makes in the gusting wind.

at least the hand towell dispenser survived

That's the fuse box!

As for a new roof. I'm still thinking about the design - probably a pent roof instead of a ridge roof.  That shouldn't divert the air flow in a manner that causes lift.  But I need to do some further research.