After some advice

[steviemac500]

I’ve had an observatory for a few years. Bought off a friend. It’s a solid construction, metal framed with a fold out roof. It’s getting old and very leaky, and to be honest, it’s probably over engineered. I’m thinking of re jigging it perhaps with  a sliding roof. Not sure where to start though. I think I’d want to removed the wood walls and perhaps replace the steel frame with timber and keep the floor. I’ve attached some pictures to give you an idea of its construction.  Any advice would be appreciated. 
Steve

[Peter Drew]

The basic construction looks pretty good and worth refurbishing.  As a mechanical engineer I would favour retaining the steel structure, a wood worker may differ.  🙂

[apaulo]

it depends on where and why its leaking, then its how much you want to spend on it.  any obs is better than none.

[malc-c]

I think if you tried to convert it to a ROR you'll run into some issues.  One being clearance as you will need to brace the roof with some sort of truss arrangement.  The fact its made from steel section makes the structure fairly solid and less likely to flex.  I would agree with a couple of other posts that it might be more prudent to try and fix the leaks or try and design a way the two halves of the roof overlap so as to prevent water ingress.  Possibly replace the OSB with T&G boards over a membrane to help keep the rain out.  Particle board is not really ideal IMO as it will swell and crumble due to damp and wet.

[steviemac500]

I live in Cyprus. The weather hits both ends of extreme and I think over the years the wood has expanded and contracted so much. The roof also collects a lot of moisture throughout the night so if I have to close it in a hurry, I can’t as the water will fall into the observatory. I think replacing the walls would be easiest and cheapest but I’d like to do something about the wet roof. 

[steviemac500]

Yes I think that’s the main problem the type of wood. Is T & G tongue and groove?

[mikeDnight]

If it were mine, I'd probably keep the steel frame and reclad the walls with 1/2" or 3/4" ply, clad on the outside with plastic cladding, (same as on the roof)

You could use angle iron runners attached to the top of the walls that extend out to an H frame. The roof itself would run easily on 5" wheels. It would mean reroofing so that the apex is sealed, and a rubber skirt around the roof edge. Below is a pic of my friends observatory similar to yours. No leaks!

 

Alternatively you could raise the walls so you could have a flat run-off roof giving you more protection from wind and stray light. The roof on mine is 1/2" ply covered with rubber roofing material. It's 12 years old this coming April and is easy has never leaked. Below are a few pics. I built my runners and the H frame from angle iron. If you place the wheels 1/3rd in from the roof edge, you won't need a long external runner.

This pic shows the strong angle iron H frame and the position of the 5" wheels.

Here the roof is closed, showing the H frame along with the rubber roofing, which also acts as a skirt and rests in the gutter.

And this final pic shows the angle iron runner  terminating about 3/4 of the way along the top of the wall. No need for it to run the entire length as the 5" wheels are set one third of the way along the roof.

Edited January 15, 2023 by mikeDnight

[Mr Spock]

Looking at it you have two main problems to solve.
Firstly the wood hasn't been treated properly which is why it's being affected by moisture.
Secondly a metal/other thin material roof is a dew magnet. It needs fully insulating to prevent dew formation.

[saac]

3 hours ago, steviemac500 said:

Yes I think that’s the main problem the type of wood. Is T & G tongue and groove?

Yes T&G is short for Tongue and Groove.  It should be a relatively straight forward task to replace the existing sheet wood walls with T&G, you could then paint the outside (preservative) to suit.  You may have to fit a few vertical posts in the walls to allow you to secure the T&G cladding but that shouldn't be difficult. You could refurbish the roof with suitable shingles or standard roofing felt to sort out the leaky roof.  If you are getting significant condensation then a generally effective solution is to make sure you have good ventilation; maybe think about installing some high and low level ventilators - pressed steel with pre cut grills or plastic versions are readily available.  

Jim  

Edited January 15, 2023 by saac

[steviemac500]

Thanks for all the advice. The condensation only occurs when the roof is open not when closed so I could do with something to stop that happening. Maybe a different material? Would polystyrene insulation prevent the moisture?

[mikeDnight]

3 hours ago, steviemac500 said:

Thanks for all the advice. The condensation only occurs when the roof is open not when closed so I could do with something to stop that happening. Maybe a different material? Would polystyrene insulation prevent the moisture?

That's one of the problems with a flip top roof as dew forms on the upside surface. If the underside of the roof faces down when open, as with a sliding roof, you won't get the dew formation on the underside.

[Swoop1]

When the roof is open, do the leaves lay supported flat? If so, a couplyof tarpaulin sheets thrown over them should help with the condensation.

You could also consider re-engineering the roof so the leaves stay top up but slide down along guides like an extendable table?

I agree with others re keeping the frame as is and re cladding.

[whipdry]

From what's visible in the pictures posted the gable end walls look fine, can't see any water damage, it's the side walls that have the water/damp issues... is this from condensation running down the inside of the roof or rain leaking in at the eaves? 

 

Peter

[steviemac500]

On 18/01/2023 at 14:59, Swoop1 said:

When the roof is open, do the leaves lay supported flat? If so, a couplyof tarpaulin sheets thrown over them should help with the condensation.

You could also consider re-engineering the roof so the leaves stay top up but slide down along guides like an extendable table?

I agree with others re keeping the frame as is and re cladding.

HI, no the roof opens up to from a V shape so the water from condensation collects.

 

On 18/01/2023 at 17:15, whipdry said:

From what's visible in the pictures posted the gable end walls look fine, can't see any water damage, it's the side walls that have the water/damp issues... is this from condensation running down the inside of the roof or rain leaking in at the eaves? 

 

Peter

Hi Peter. The damage is really from rain. We get extremes of heat and then heavy rain and cold in Cyprus so over time the walls have warped.