First obsy build (part 2)

[rodrigol]

Progress since yesterday. Here is a shots of the roof and walls structures. The roof is in the open position.

 

 

 

Here is a series of shots showing the open/close and the swing-arm:

 

 

Towards the end of the day I finished the swing-arm counterweight cages:

 

A here is the roof in action. It's not a perfect swing but it's solid.

 

[cardigan wearer]

Not seen your novel roof design before, but its giving me some ideas about where I could build an obsy. Thumbs up to you, just make sure you can lock it in place so it cant crash down on you or the scope if its windy.

[Daz69]

Good idea for the roof, but how are you stopping water ingress where the roof meets the walls, as there doesn't appear to be any overlap of the walls? 

 

[rodrigol]

6 hours ago, cardigan wearer said:

Not seen your novel roof design before, but its giving me some ideas about where I could build an obsy. Thumbs up to you, just make sure you can lock it in place so it cant crash down on you or the scope if its windy.

It does look like  a sail,  right?   The idea is to add heavy duty hooks to hold it in position when opened from the outside. I'm not sure where to put these but they would seem right to secure  the tail/bottom end. Many thanks for the comments :-) 

 

[rodrigol]

3 hours ago, Daz69 said:

Good idea for the roof, but how are you stopping water ingress where the roof meets the walls, as there doesn't appear to be any overlap of the walls? 

 

Hi, 

At the moment the roof frame fits flush to the a new wall frame. There will be an overhang on the front and the sides but have yet to figure out how to do it. Suggestions are very welcome :-) 

[alanjgreen]

It could get hot in there with the clear roof.

you could fasten rubber over the roof and over the edges to make it cooler inside, overhang the rubber to take rain past the join (roof and wall) so the rain water stays outside.

You can always fix things on the outside of the rubber but at least you have a membrane underneath.

 

Also be aware that any gaps (between roof/wall) like this will let the wind in.

[rodrigol]

9 minutes ago, alanjgreen said:

It could get hot in there with the clear roof.

you could fasten rubber over the roof and over the edges to make it cooler inside, the overhang could take rain past the join (roof and wall) so the rain water stays outside.

Hi, 

Thanks for the comments :-)  The summer temperatures worry me with the clear roof so ventilation is going to be critical. Ventilation bricks or just holes with a mesh at roof height as well as at floor height are in the pipeline. Perhaps with PC cooling fans? While on the topic of ventilation: condensation is a must-think-about.  So currently, a heater fan (see second picture)  set to run a little above ambient and controlled via a timer at 30 minutes intervals, seems to keep everything dry. 

[alanjgreen]

I use 6 of these stainless steel clamps to lock my roof shut

http://www.brauer.co.uk/vertical-stainless-steel-latch-clamps-s301.aspx

My roof is also heavy.

there are some latch clamps in this thread, although I like the brauer better

 

I would suggest as your roof looks lightweight that you may want to consider a "backup" plan for those forcast "very strong wind" occasions

You could add additonal "turnbuckles" that you put on during those occasions or when you go on holiday - to be double sure the roof stays on.

http://www.screwfix.com/p/hardware-solutions-turnbuckle-hook-zinc-plated-3-8/57029?cm_sp=Search-_-SearchRec-_-Area2&_requestid=1984468

You can see turnbuckles in this thread

 

[alanjgreen]

6 minutes ago, rodrigol said:

Hi, 

Thanks for the comments :-)  The summer temperatures worry me with the clear roof so ventilation is going to be critical. Ventilation bricks or just holes with a mesh at roof height as well as at floor height are in the pipeline. Perhaps with PC cooling fans? While on the topic of ventilation: condensation is a must-think-about.  So currently, a heater fan (see second picture)  set to run a little above ambient and controlled via a timer at 30 minutes intervals, seems to keep everything dry. 

Can't comment on whether that is a good solution or not. I can say that I use a dessicant de-humidifier.

If you go the de-humidifier route make sure to get the "dessicant" one as they work at low temperatures.

 

[alanjgreen]

8 minutes ago, rodrigol said:

Hi, 

Thanks for the comments :-)  The summer temperatures worry me with the clear roof so ventilation is going to be critical. Ventilation bricks or just holes with a mesh at roof height as well as at floor height are in the pipeline. Perhaps with PC cooling fans? While on the topic of ventilation: condensation is a must-think-about.  So currently, a heater fan (see second picture)  set to run a little above ambient and controlled via a timer at 30 minutes intervals, seems to keep everything dry. 

put the ventilation holes on the side where "wind" is least likely to blow from.

 

[rodrigol]

I've got no experience with dissicant dehumidifiers and was thus wondering if you could recommend a link? 

Thanks!

[rodrigol]

8 hours ago, alanjgreen said:

I use 6 of these stainless steel clamps to lock my roof shut

http://www.brauer.co.uk/vertical-stainless-steel-latch-clamps-s301.aspx

My roof is also heavy.

there are some latch clamps in this thread, although I like the brauer better

Battery 

I would suggest as your roof looks lightweight that you may want to consider a "backup" plan for those forcast "very strong wind" occasions

You could add additonal "turnbuckles" that you put on during those occasions or when you go on holiday - to be double sure the roof stays on.

http://www.screwfix.com/p/hardware-solutions-turnbuckle-hook-zinc-plated-3-8/57029?cm_sp=Search-_-SearchRec-_-Area2&_requestid=1984468

You can see turnbuckles in this thread

 

Hi, 

Many thanks for tips! I've seen folks use turnbuckle for their roll-out roofs here. That seems quite appropriate. My roof is in direct contact with the walls and that made me think that latches (I've got two on the inside)  or adjustable horizontal clamps,  like the one below,  are one way forward. Any experiences you can share with these? 

[alanjgreen]

9 hours ago, rodrigol said:

I've got no experience with dissicant dehumidifiers and was thus wondering if you could recommend a link? 

Thanks!

I use this one

http://www.appliancesdirect.co.uk/p_dd122fw-simple_ecoair-dd122fwsimple-dehumidifier/version.asp?refsource=Apadwords&gclid=CLmMvrvxw9ECFVEo0wod2U4D5A

shop around on price, can't recall where I got in online?

[Skipper Billy]

I use one of these in my obsy - works VERY well.

Whichever you choose make sure its not only a dessicant type (compressor types do nothing at less than 10º) and that it has a continuous drain function and that you lead the drain outside the obsy or you will just be recycling the water in the obsy over and over again !!

Great project - its a lot of fun isnt it !!??

Link - http://www.dehumidifiersuk.com/eco-air-dd122fw-simple-7-litre-low-temperature-desiccant-dehumidifier.html

[alanjgreen]

1 hour ago, rodrigol said:

Hi, 

Many thanks for tips! I've seen folks use turnbuckle for their roll-out roofs here. That seems quite appropriate. My roof is in direct contact with the walls and that made me think that latches (I've got two on the inside)  or adjustable horizontal clamps,  like the one below,  are one way forward. Any experiences you can share with these? 

The brauer that I linked above are latches, I use 6, three on each side. Looking at your roof design, I would put 2 on all 4 sides. You need it down tight. I went with stainless steel to avoid rust.

if you get wind from any particular direction then maybe put extra on that side.

assume that the wind will find the weak point, and then remove the weakness.

[Oddsocks]

10 hours ago, alanjgreen said:

The summer temperatures worry me with the clear roof

Paint the inside (or outside) of the roof with aluminised reflective flat-roof protection paint, it will reduce internal heating by more than 95%, most DIY stores and builders merchants carry it in stock though not all types are suitable for polycarbonate (bitumen based paints are not suitable), and often not available in sizes less than 5l, plus it will cut all light transmission through the roof.

Otherwise, greenhouse/conservatory white solar reflective paint, applied to the inside, that is suitable for polycarbonate, cuts heat transmission by 90% but allows around 65% light through and usually available in small quantities, relatively inexpensive but disadvantage is that it is easily scratched so needs regular touch-up, sample link : https://www.amazon.co.uk/Reflect-Polycarbonate-Conservatory-Shading-Greenhouse/dp/B00AC1ZPZ2

Another alternative is self adhesive solar reflective window foil applied to the inside, this is tougher than paint but quite a bit more expensive and not so effective thermally, typically reducing heat transmission by around 70% to 80% while allowing 50% to 60% light to pass.

https://www.amazon.co.uk/Silver-Reflective-Window-Control-Privacy/dp/B002QEVFFC

All the above options do not add significantly to the weight of the roof but will reduce heating significantly.

In your posted image the roofing looks like double skinned polycarbonate, if so, make sure the ends of the polycarbonate channels are fully sealed at the upper ends to prevent water entering and sealed at the lower ends with removable stoppers/closed cell foam etc, this makes the roof behave more like double glazing and cuts down on dew formation on the inside of the roof which is a problem for most flat roof designs. The lower end stoppers/closed cell foam can be removed occasionally during summer to dry out any trapped condensation in the channels and prevent the roof turning green.

 

9 hours ago, rodrigol said:

I've got no experience with dissicant dehumidifiers and was thus wondering if you could recommend a link? 

For a dessicant type dehumidifier these work well (linked below) and are very efficient, use the supplied continual drain hose to route removed water outside the observatory otherwise you will be emptying the drain tank daily. Depending on your settings for target humidity, fan speed, how many hours per day you run it, the volume of the observatory and the rate of air change they can cost as much as £20 to £40 or more per month in electricity charges.

I use one of these: http://www.dry-it-out.com/DD822-Graphite-dehumidifier

I use mine only during the night, typically for around eight hours, October to March, and set to 60% humidity with fan speed low, it costs me £8 per month on average for electricity in a small fibreglass dome observatory that is very draughty (or well ventilated depending on your interpretation) so I am dehumidifying the garden most of the time as well!

If installing one using the continual drain hose option then remember the drain hose has to slope downwards away from the dehumidifier and where it exits the observatory it needs to be lagged to prevent it freezing during a cold snap.

 

[rodrigol]

4 hours ago, Oddsocks said:

Paint the inside (or outside) of the roof with aluminised reflective flat-roof protection paint, it will reduce internal heating by more than 95%, most DIY stores and builders merchants carry it in stock though not all types are suitable for polycarbonate (bitumen based paints are not suitable), and often not available in sizes less than 5l, plus it will cut all light transmission through the roof.

Otherwise, greenhouse/conservatory white solar reflective paint, applied to the inside, that is suitable for polycarbonate, cuts heat transmission by 90% but allows around 65% light through and usually available in small quantities, relatively inexpensive but disadvantage is that it is easily scratched so needs regular touch-up, sample link : https://www.amazon.co.uk/Reflect-Polycarbonate-Conservatory-Shading-Greenhouse/dp/B00AC1ZPZ2

>> rodrigol - This is the kind of stuff I didn't know about until one starts asking here! Many thanks for this giant tip - this is the stuff I will go for! :-)

Another alternative is self adhesive solar reflective window foil applied to the inside, this is tougher than paint but quite a bit more expensive and not so effective thermally, typically reducing heat transmission by around 70% to 80% while allowing 50% to 60% light to pass.

https://www.amazon.co.uk/Silver-Reflective-Window-Control-Privacy/dp/B002QEVFFC

All the above options do not add significantly to the weight of the roof but will reduce heating significantly.

In your posted image the roofing looks like double skinned polycarbonate, if so, make sure the ends of the polycarbonate channels are fully sealed at the upper ends to prevent water entering and sealed at the lower ends with removable stoppers/closed cell foam etc, this makes the roof behave more like double glazing and cuts down on dew formation on the inside of the roof which is a problem for most flat roof designs. The lower end stoppers/closed cell foam can be removed occasionally during summer to dry out any trapped condensation in the channels and prevent the roof turning green.

>> rodrigol - The roof panels are sealed quite professionally. Piotr did quite a job building this. I will post some pictures later on with details outside as well as inside so you can see. 

For a dessicant type dehumidifier these work well (linked below) and are very efficient, use the supplied continual drain hose to route removed water outside the observatory otherwise you will be emptying the drain tank daily. Depending on your settings for target humidity, fan speed, how many hours per day you run it, the volume of the observatory and the rate of air change they can cost as much as £20 to £40 or more per month in electricity charges.

I use one of these: http://www.dry-it-out.com/DD822-Graphite-dehumidifier

I use mine only during the night, typically for around eight hours, October to March, and set to 60% humidity with fan speed low, it costs me £8 per month on average for electricity in a small fibreglass dome observatory that is very draughty (or well ventilated depending on your interpretation) so I am dehumidifying the garden most of the time as well!

If installing one using the continual drain hose option then remember the drain hose has to slope downwards away from the dehumidifier and where it exits the observatory it needs to be lagged to prevent it freezing during a cold snap.

>> rodrigol - I'm browsing this one - again, thanks for the tip. I'm a bit hesitant at this stage due to the price. A good eyepiece that is! But it does look as if this is going to be the thing to go for medium term.

 

4 hours ago, Oddsocks said:

 

 

[Daz69]

I use a 4" wall fan that vents through the wall in my bird house, set for 20 minutes every 2 hours, daily except at night. It shuts off at 8pm and restarts at 8am.

A PC fan won't shift enough air IMO, but several might. A suggestion would be to have them high on one wall and low on the opposing wall to increase the cold/warm transfer. 

A butyl skirt around the roof/wall joint will be ok so long as you make sure that the butyl on the roof edge joint is 100% sealed to avoid water seeping behind it and inwards. Personally, if I went with this idea, I would seal a butyl skirt around the roof edge long enough to sit over the roof/wall joint, using Sikaflex adhesive, and then another strip over that top joint by 50% and lay the remainder underneath the corrugated sheet on top. 

[rodrigol]

11 hours ago, Skipper Billy said:

I use one of these in my obsy - works VERY well.

Whichever you choose make sure its not only a dessicant type (compressor types do nothing at less than 10º) and that it has a continuous drain function and that you lead the drain outside the obsy or you will just be recycling the water in the obsy over and over again !!

Great project - its a lot of fun isnt it !!??

Link - http://www.dehumidifiersuk.com/eco-air-dd122fw-simple-7-litre-low-temperature-desiccant-dehumidifier.html

Indeed, this is great fun! And even when the weather is no good for watching the stars! Thank you very much for the tips. It does look as if the DD122FW is the think to go for :-)

 

[Oddsocks]

11 hours ago, rodrigol said:

It does look as if the DD122FW is the think to go for :

That DD122FW dehumidifier you are considering is available from several different suppliers rebadged with a different model number and name. Currently it is also available with a three year warranty instead of two and £10 cheaper plus free delivery here: http://www.dry-it-out.com/dd1-simple-desiccant-dehumdifier

If you compare specs I think you will find it is identical to the DD122FW.

 

[alanjgreen]

I got mine here

https://www.energybulbs.co.uk/ecoair+dd122fw+simple+desiccant+dehumidifier+(dd122)/2944267352

cheaper still

[rodrigol]

Many thanks for the tips regarding the dehumidifier. I may have to buy sooner than planned.

 

[Skipper Billy]

Make sure you lag the outlet pipe - it freezes up very quickly and stops it working when you most need it!

[rodrigol]

Dehumidifier has been ordered and here are some picture that may help explain where I'm at the moment:

This is how the roof looks from above. I hope you can see the panels are hopefully well laid out. There is an overhang at the back to ensure that running water does not run down the back wall.

Below is a view of the front. Still work to do. As discussed above, and again thanks for everyone for their comments, I need to seal and sort out the overhang.

 

Below if a view of the side. It's quite flush to the wall frame. The swingarm spacer 4x4 there is not ideal but it works and makes the opening and closing a real doddle. I may post a video at some point soon.

 

 

Below two views from the inside. Everything is nice and flush. No drafts but I will need to sort out ventilation at some point and the bolting down of the roof structure to the wall frame.

Another weekend coming. Hoping it stays dry and I can actually start moving stuff in. 

Once again, if anyone has comments, I will be very grateful.

 

 

[SlimPaling]

Hi ... I spotted your posts about you new observatory with hinged roof .... looks excellent :-)

I finished my own observatory last summer which I am pretty pleased with .... it uses a twin hinged roof. I thought that you might like to see some pikkies of it.

I didn't want a roll-off roof as it would take up too much room in the garden ... so I had to come up with a more compact design.

It all started with some accurate scale models cut out on a laser cutter to test out my ideas and positions of the various pivots and links ... which quickly established that the idea would work as planned. The finished roof works well and doesn't take much effort to open it by hand .... at the moment I don't have any plans to try to "motorise" it yet ... in fact I'm not too sure if I can do it anyway!

To stop the rain getting into the apex one panel has a custom made cap which overlaps the top of the other panel ... it works.

Regards

Mike