New observatory project!

[Emmanuel Marchal]

Here we go, i've started digging the pier hole.

Pouring concrete hopefully this week. And the design the observatory is taking shape (as you can see it serves as a normal garden shed as well for the mower!).

 

[Emmanuel Marchal]

Concrete for the pier is poured. I've used an old chimney pipe to get it a bit higher and 4 12" rods bent in L shape. 8 bags of balast and 2 of concrete later and it seems I now have a stable base. Also started getting the shape of the obsy down which will be 2.20m x 4.40m. Hoping to finish the floor this coming weekend!

[Emmanuel Marchal]

And the pier is up!

 

[Davie]

I'll be impressed if you only have a mower in the storage part 

[Emmanuel Marchal]

Finally managed to find a bit of spare time to progress. Basic structure is coming up nicely. I've been wondering a lot about the height of the walls. I'm 6'4" so want to have enough height to stand. but that creates a bit of a pb as the walls are definitely too high on the south side. So i'm going to have to make a wall that can fold. more design to come. 

[Emmanuel Marchal]

And the 4 walls are now up. including the shiplap on the back wall facing the fence. I made that one with PVC shiplap as I won't be able to access it for maintenance. so hopefully good for 15 years to come!

I've also made the south facing open able to open up. Design is heavily inspired by the great job of malc-c

The window and double door are recovered from my old house before we improved it. I hope once all covered in shiplap it will look ok.

[Physopto]

Have you put your wires into a conduit? Mice love wires to chew on especially under a accessible floor!

Derek

[Emmanuel Marchal]

On 5/5/2016 at 10:28, Physopto said:

Have you put your wires into a conduit? Mice love wires to chew on especially under a accessible floor!

Derek

hum no. but not too late.... the wire is armoured but you're right better safe than having to redo the floor...

[Physopto]

Be just like the little blighters to chew through the outer covering and there's your waterproof cover gone.

Maybe use blue water pipe for a cover as it is cheap and in long lengths.

[Emmanuel Marchal]

16 hours ago, Physopto said:

Be just like the little blighters to chew through the outer covering and there's your waterproof cover gone.

Maybe use blue water pipe for a cover as it is cheap and in long lengths.

didn't think about that. not a bad idea. I was thinking simple conduit like this http://www.screwfix.com/p/tower-conduit-heavy-gauge-20mm-x-2m-length-black/70541

[Physopto]

21 minutes ago, Emmanuel Marchal said:

didn't think about that. not a bad idea. I was thinking simple conduit like this http://www.screwfix.com/p/tower-conduit-heavy-gauge-20mm-x-2m-length-black/70541

Yes tried that over 30 years ago. The joints can cause problems when pulling new cables if not smoothed off ans internally chamfered. Also can leak supprisingly. Found one several years later full of water under ground. Then the white version is short lived in UV light forum the Sun. The blue water pipe seems to last for ever, easy to lay with no underground joints, unless very long lengths. It is cheaper as no joints needed most times so no leaks. I used several for differet wires and kept them well separated when doing my fish house ( filtration ). So alarm circuit was totally separate to the mains so no capacitive/inductive effect on alarm circuit.

Derek

[Gina]

I think the blue plastic water pipe is available in lengths up to 100m.  Used it in the field to carry water from a small dam and reservior up the hill to taps and water troughs further down.  Rats and mice don't seem to touch it - unlike other things.  I also used it for the underground cable feed to my observatory.  It's very tough.  Available from farm supplies shops and web sites.

[Physopto]

I agree Gina, also from if all else fails, Wicks but at premium costs and shorter lengths.  25mm x 50 mtr at Screwfix £31.50

 

[Emmanuel Marchal]

2 minutes ago, Physopto said:

I agree Gina, also from if all else fails, Wicks but at premium costs and shorter lengths.  25mm x 50 mtr at Screwfix £31.50

 

Thanks Gina and Derek.

I'll steer clear of the pvc pipes then.

[Gina]

Got ours from Mole Valley Farmers together with fittings, one of our local farm supplies shops eg. 20mm x 100mm MDPE blue water pipe.  That's the smallest bore and bigger sizes are available eg. 25mm, 63mm etc. Shorter lengths also available.  Two types are available - BLUE for underground use and BLACK for overground, having UV protection.  I've used both for water distribution around the smallholding.  Yes, also available form DIY stores (may cost more).  Main water supply here and to the neighbours is also in this type of pipe - coming from a spring with filters and reservoir tanks further up the hill.

[psamathe]

Re: mains cabling (I'm no expert so just recounting my personal experience)

When builders built my garage, they put in the supply cable and then I used the dreaded word "Part P" at which point they called in a certified electrician who rejected it and made them start again (the supply cable was rejected for only being 20A and he wanted 32A).  But they still just buried armoured cable in the ground (putting the special yellow tape over the top).  I don't know about the UK but in France they have regs about the colour of conduit and what runs through it.  So having water supply pipe but running mains electricity ...

I don't know if it would count as outdoor cabling from a inspection perspective but remember that these days Part P certificates are required (and vital when selling a property).  Assuming you are not certified tester yourself then maybe find a cooperative certified electrician.  When I re-wired upstairs I got my electrician in to "quote" and then did all the "I appreciate how busy you are", "maybe I can make your life easier by doing the manual unskilled bits", etc. and soon ended-up with him telling me what to do and at what stage he would need to come-in to inspect, etc. and ended-up paying £25 for his inspections/Part P certificate.  Most electricians are not that helpful.

If you are installing mains cable house to observatory, I'd also suggest adding several Cat 6 ethernet cables to the run (or even fibre if you want).  Cat 6 cable (on drums) is cheap and if you ever start sitting indoors networked to the observatory, then having that cabled network is useful.  Maybe also a phone line ?

I'm a great believer in putting in as many cables as you could possibly ever want when doing an installation as it is so much easier to do it all at the same time than to start to add new feeds later.

Ian

[Physopto]

Good point Ian.

It depends upon if it is wired permanently into the mains I believe. You can use a junction indoors and connect that to a 13 amp socket by plug. Maybe not he best method but frees you from  a permanent installation. The cable can be put into black water pipe as Gina has mentioned rather than the blue.

To be quite honest the best method is to use a ring main anyway from the main supply fuse box in the house. In the end it depends upon what you want and can afford. As long as it is safe, properly tested and certified if needed. A single high amperage cable will be OK if it is a plug connection and the current is limited to well below the cable rating, 13 amps maximum for the plug.

If you do not know what you are doing always get an certified electrician to do the work.

Derek

[Emmanuel Marchal]

Agree with all your comments. I had the cable installed by an electrician who connected it from an external socket that was installed specifically for the observatory. I will have him come back to wire the obsy as well.  Playing safe here

[psamathe]

8 hours ago, Physopto said:

Good point Ian.

It depends upon if it is wired permanently into the mains I believe. You can use a junction indoors and connect that to a 13 amp socket by plug. Maybe not he best method but frees you from  a permanent installation. The cable can be put into black water pipe as Gina has mentioned rather than the blue.

To be quite honest the best method is to use a ring main anyway from the main supply fuse box in the house. In the end it depends upon what you want and can afford. As long as it is safe, properly tested and certified if needed. A single high amperage cable will be OK if it is a plug connection and the current is limited to well below the cable rating, 13 amps maximum for the plug.

If you do not know what you are doing always get an certified electrician to do the work.

Derek

From my own re-wiring (and questionable memory) a lot depends on the cable run distance (as to whether you can ring main it or not).  And that can also affect the earthing requirements.  So in the case of my garage supplied from it's own dedicated breaker in the house, the house supply has it's earth provided by the electricity supply (no spikes in the ground) but the cable run distance to the garage meant it needed an earth spike in the ground (i.e. could not take it's earth through the supply cable from the house).

With spurs I believe you are only allowed one spur per ring main.  So when I was working on my upstairs cabling I ended-up extending the ring (as there was already a spur on the ring).

Personally I'm a great believer in RCDs, so I'd always say that if you house electrics are old enough not to have an RCD then I'd suggest getting one fitted.  And if there is not room you can always have an MCB swapped for an RCDO which is a single width so can normally just be a simple swap-out - providing RCD protection on the single circuit.

So I must emphasise I am not a professional and thus cannot offer advice (only my amateur thoughts).  And the beauty of forums like this is that there are bound to be several processional electricians here who can come and post everything I'm wrong about.

Ian

[Emmanuel Marchal]

Finally managed to make a bit of progress on the build. The electrical armoured cable is now in, protected by steel pipe. I've also installed a membrane under the floor as it was a real slug fest below it.

I've also built the roof. Not entirely finished but it seems to work ok. I've used simple castor wheels 40mm in diameter. They work like a charm

http://www.ebay.co.uk/itm/PACK-OF-6-FIXED-WHEEL-BLACK-NYLON-CASTORS-40mm-x-17mm-WHEEL-66-x-25-PLATE-

 

Next week i'll focus on the cladding. considering Cedar to make the obsy looks quite nice but is also maintenance free. I also need to get the roofing protection. Considering EPDM membrane as it seems quite more durable and maintenance free as well.

Has anyone got experience with EPDM? Is it easy to install?

[Physopto]

I would not use EDPM, I believe it will not breath. Then any damp will rot the wood. I would look at Tyvek as it is breathable, not sure of the price though. See if a builder has off cuts cheaper. Last if possible leave a small gap between the outer wood and the Tyvek to allow air to circulate.

Derek

[Davey-T]

I've had an EPDM liner in my pond for over 20 years but that obviously isn't bothered by damp 

Don't know if Tyvek is UV proof as it wouldn't usually be exposed to sunlight.

Dave

[Physopto]

Tyvek is used all over the world as far as I know. Never used it but from what I have seen I would. I have seen houses covered in it left unclad  for months without any signs of damage. 

[LongJohn54]

EPDM is easy to install.  It's quite heavy; a piece 4m x 3m weighs about 30Kg and it half killed me lifting onto the roof.   You can cut it with household scissors or once glued down use a stanley knife to trim.  It's essential to lay it onto a dry surface (my roof is OSB) on a warm dry day for best results.

The rubber will be supplied folded and needs to be laid out flat for an hour to ease out the creases (photo).  The acrylic adhesive has about 30mins working time and will set in 6 hours.  You can use a paintbrush or roller to slap this on.  Buy cheap ones and bin them after use. Its not worthwhile trying to clean them.  The contact adhesive goes tacky in 10mins so use for small areas at a time.  It sticks instantly and cannot be removed so be careful when folding the EPDM around corners and other fiddly areas.

I bought Classicbond from here - http://www.rubber4roofs.co.uk/  There are other suppliers as well.   Click the Training menu and see the videos, instruction manuals and FAQs.  I found them very helpful.

[Gina]

Yes, it's what I used on my observatory roof - both ROR and warm room - very east to apply and makes a good job.