Astrokev's ROR - The Build

[Astrokev]

So, a few pictures taken this evening. Just a few finishing touches to make to the breathable membrane, which I'll do tomorrow (thin strips around the top of the walls and a bit underneath the door). Looks a bit more like a building now, rather than a climbing frame  ?.

Next job is to get the cladding, but before then I've realised that it would be helpful to make the door frame to define the edges I need the cladding to but up against, so may start this tomorrow also if I have time.

[JamesF]

I've had a couple of weeks off from my build too, but now I'm back in the country I shall start again tomorrow I think.

James

[Astrokev]

1 minute ago, JamesF said:

I've had a couple of weeks off from my build too, but now I'm back in the country I shall start again tomorrow I think.

James

Good to hear. I was wondering where you'd gone!

[JamesF]

Ah, as posted elsewhere, been up a mountain in southern Spain (with a telescope) for a couple of weeks being bitten to shreds by insects, but it did mean that I got a decent view of much of the lunar eclipse.

Drove to Malaga airport this morning, returned to Bristol care of Captain Easyjet (who subjected us to a bit of a hairy landing, I have to say) then had to reacquaint myself with driving on the correct side of the road and changing gear left-handed to get home.

James

[Astrokev]

Sounds grand (apart from the landing). A long time since I've had a proper astro holiday ?.

Hope you got some good images?

Edited August 1, 2018 by Astrokev

[JamesF]

Yes   Raised the shutter count on my 450D by about 700 following the eclipse from when it was full to the end.  I've barely scratched the surface with processing yet, but posted an early sub here:

 

James

[Gina]

Welcome home James ?

[Astrokev]

....and a bit of a rubbish picture from inside the scope room after finishing the membrane at the top of the walls. 

[Yawning Angel]

On ‎01‎/‎08‎/‎2018 at 22:24, Astrokev said:

So, a few pictures taken this evening. Just a few finishing touches to make to the breathable membrane, which I'll do tomorrow (thin strips around the top of the walls and a bit underneath the door). Looks a bit more like a building now, rather than a climbing frame  ?.

Next job is to get the cladding, but before then I've realised that it would be helpful to make the door frame to define the edges I need the cladding to but up against, so may start this tomorrow also if I have time.

 

 

Looking very nice, Kev! Are you cladding directly over the top of the membrane, or running batons?

[Kev M]

Looking good , starting my build this weekend, will have to get some pictures taken ( it will look remarkably like your design, apologies....lol )

Kev

[Astrokev]

8 hours ago, Yawning Angel said:

Looking very nice, Kev! Are you cladding directly over the top of the membrane, or running batons?

Thanks!

cladding straight into the membrane. 

Waiting for the weather to cool off before I buy the cladding. Not recommended to clad in 30' plus temp!

[Astrokev]

1 hour ago, Kev M said:

Looking good , starting my build this weekend, will have to get some pictures taken ( it will look remarkably like your design, apologies....lol )

Kev

Thanks Kev. 

No need to apologise - most of my designs have been pinched off other people!

good luck with your build. Look forward to seeing some pictures ?

[Astrokev]

Still too hot to get the cladding, but I think it's getting closer ? .

So, whilst I'm waiting I've been doing other smaller jobs -

The timber merchant didn't have any door-sill timber, so will be picking this up this week to do the door frame.

This morning I trimmed the fixed roof EPDM at the sides and the back (north) end of the roof. Trimming  the sides needed doing for when I make the wrap-around retention mechanism for the ROR.

Also bought some mini guttering to fix at the north end of the fixed roof, except that they'd run out of brackets (I don't seem to be having much luck at the moment with stock availability!). I'm promised these will be in stock on Wednesday.

To finish my pottering  today I attached a thick polythene sheet to the ROR to hopefully keep the rain out (if we ever see rain ever again ? ).

[Gina]

IF!!!

[Dr_Ju_ju]

Metcheck says Friday, I'll believe it when I see it...

[Astrokev]

The nice BBC lady mentioned thunderstorms in the south east later this week, so best be prepared just in case !

[Kev M]

As soon as you mount the scope it will cloud over and rain......known scientific fact !

 

[Yawning Angel]

On ‎03‎/‎08‎/‎2018 at 20:41, Astrokev said:

Thanks!

cladding straight into the membrane. 

I was in 2 minds about doing that too. It seems that batons and an air gap is worthwhile if it's insulated, to allow vertical airflow, but that leads to needing insect mesh to protect the void. Argh!

[Astrokev]

7 hours ago, Yawning Angel said:

I was in 2 minds about doing that too. It seems that batons and an air gap is worthwhile if it's insulated, to allow vertical airflow, but that leads to needing insect mesh to protect the void. Argh!

Yes, with membrane behind the cladding I can see the advantage of having an air gap, which would allow some movement of air, thus helping to dry out the inside face of the cladding if water got behind it. That said, I've not seen anyone adopt this approach on SGL. It's also true to say that not many people seem to use a membrane so, in this instance, there's probably less risk of water getting trapped between the timber and a barrier membrane.

Hopefully, the fact that the membrane is breathable will allow water to evaporate through it (I guess that's what it's for!) so I'm not that concerned about water retention. I'd be more concerned if the membrane was not breathable ie. just polythene sheet, which I've seen some people use. All that said, providing the cladding has no gaps then water shouldn't penetrate behind it (I say shouldn't, but it's all about minimising risk, right?  ?!).

[Gina]

I used a breathable membrane between framework and cladding but I don't really know what it does.  Just took advice on here.

[nightvision]

This explains them very well: https://www.designingbuildings.co.uk/wiki/Breather_membranes_for_buildings

Edited August 8, 2018 by nightvision

[Astrokev]

Thanks Tony. Very informative and interesting.

This all looks good, but I've not seen anyone build an obsy like this. Some use breather membrane on the outside with cladding straight on top (as I'm planning to do). Some have put a sheathing board beneath the membrane, but with no vented cavity.

At the end of the day, I think it's whatever feels right to you. It's worth remembering also that we're essentially building a glorified shed, and not a place to live in (although I'm sure some would live in their obsy's if they could ?).

[Astrokev]

23 hours ago, Gina said:

I used a breathable membrane between framework and cladding but I don't really know what it does.  Just took advice on here.

Was your membrane breathable Gina? It looked more like polythene vapour barrier, which is non-permeable. Not saying there's anything wrong with this, but it didn't look breathable. I presume you've had no problems with moisture damaging the cladding ?

[Gina]

No problem at all.  Cladding is as good as new - after 7 years.

[RayD]

A breathable membrane is only necessary if you are insulating the inside.  It allows the moisture which will build up between the insulation and the membrane to escape, preventing damp and mould, but also provides a water tight external face to prevent the insulation getting wet.  If you have nothing going on the inside as far as insulation goes, then it is not necessary to install a membrane at all, but it does provide a water barrier if your cladding starts to move.