Non-Gardener builds an Observatory, Garden Railway and even Dabbles with Plants!

Thanks, but at this point, the hard work had barely started!!!

 

17th April 2022

This was the basic plan; a converted 12 x 8ft pent roof shed, with a custom roll off roof, dropping down as it opened, so it didn't block any view of the sky. The two concrete piers would be staggered slightly, so both had a good view to the South, where stellar objects reach their highest in the sky. Adapters would then connect the concrete piers to the Equatorial telescope mounts.



Once I'd decided on the correct location, I needed to peg out the significant points more accurately and with 90 degree corners. The location of the roof runner supports were also plotted. The gap between the observatory and shed would be partially occupied by the extended hardstanding for my trailer and also some raised vegetable planters.



I made a giant set square to help me plot everything out squarely. At this point, we'd kept the base of the large tree, possibly for a table, but while I was plotting everything out, it became clear it wasn't going to work. It didn't get in the way of any part of the observatory, but was close enough not to work with the plan. It may have been ok had I not needed to move the observatory 8 inches.

In this picture, I've also started marking out the footings for the corners of the observatory. The she was going to need a level plinth to sit on.

 

18th April 2022

The observatory needed ten footings for the basic building and another three for the roof runner supports and bracing. Each hole gave up around a wheelbarrow load of earth. In the left front hole, I discovered more foundations for the World War 2 air raid shelter. I hoped I wasn't going to find too much concrete still buried.



21st April 2022

In the rear left corner, the was a large lump of concrete inside the footing hole, which I decided to leave it alone. Investigations showed it to be part of a much larger slab of concrete - part of the air raid shelter floor. Eight of the holes for the footings are shown dug out and later that day, two 12 inch diameter postal tubes arrived to form the moulds for the piers.

 

22nd April 2022

The postal tubes were given a couple of coats of dilute waterproof PVA glue to help to seal and strengthen the card in preparation for the concrete pour. I laid two high density concrete blocks, bedded on concrete, for the footing. It was cheaper to do it this way, than to just fill the hole with concrete.

One hole was done to estimate the quantities needed for everything else. Wooden posts would be mounted on top of these with metal brackets, which in turn would support the observatory floor.



At the end of the day, I balanced the two card piers in place to get a sense of the layout and space.

 

23rd April 2022

On the 23rd, I did some plotting out of the floor height with string, finding a level line over the whole floor area. The garden slopes to the right front, so the floor at one end is quite a bit higher than the other.



To help the situation, the footing with the large block of concrete in it, really needed lowering. The only way to achieve this was to use a grinder with a stone cutting disc and slowly, bit by bit, slice and break out parts of the concrete air raid shelter floor.

I didn't find the end of the slab, but lowered it enough to drop my footing a bit. The frame supporting the floor will be pretty much touching the ground here, but will be around two feet above the lawn at the other end of the observatory. I was going to need some steps from the lawn so I could enter. They will probably fold up into the doorway when not needed.

 

26th April 2022

Seven of the footings had been concreted in place and I'd run out of blocks and concrete. I was waiting for a B&Q delivery, which surprisingly was cheaper than any other building suppliers in the area. One area they failed on was timber for the floor support frame. I found that cheaper elsewhere.



The concrete was missing off the delivery when it arrived, but the driver came back later in the day with it. Annoyingly, seven bags were spilling their contents or were already setting inside the bags. Why even load that on a pallet for a customer? I made sure they came to collect them ( at their expense ) and brought enough new bags back to pick useable bags.

 

27th April 2022

The following day, the shed arrived. The pathetic excuse for a shipping pallet was crushed by the weight of the shed and the courier had loaded the whole lot onto a second pallet, but it wasn't particularly stable! It arrived just after 10am and it took me a good two and a half hours plus to slowly unpack it, load it on or in the car and drive around the back of the house.



It took around five or six loads I think. I was beginning to wonder whether I'd bought a shed or a flat-pack bungalow!! Slowly it was carried into the workshop to be checked over and ticked off the parts list. Having just cleared space in the workshop earlier that week, all of a sudden, it was full of concrete and shed.

 

29th April 2022

On the 29th, I began to lower the ground level at the highest point at the rear left. This was to allow the floor joists to sit level. It was slow going, having to cut through a number of tree roots as I worked my way lower. The tree stump was also cut lower. Next, three of the six floor panels were brought out to the workshop patio to double check the floor footprint. This allowed me to start cutting the perimeter floor joists and the corner support legs.

I slowly worked around the four sides, cutting the joists and legs, though none were screwed together. The front two corner brackets were the only two drilled and temporarily bolted to the concrete footings. The other corners would have to wait until I spent more time carefully checking the joist footprint that it was square. Two floor panels were brought out to check on the floor height. However, it was close to the end of the day, so it was time to pack up.

Over the next few days, I had general garden maintenance to do, but took a little time out each day to paint the pier tubes with three coats of Hammerite Smooth White paint.



3rd May 2022

Work outside came to a temporary halt, as I had some builders extending the concrete hardstanding beside the garage and shed. Since that was very close to the observatory location, I didn't want to be in their way, so outside jobs were left for a few days.

Instead, I had a big move around of concrete and other bits and pieces in the workshop, clearing some floor space so I had somewhere to work on modifying the shed. Once a big enough space was cleared, I laid out two end panels to start working how and where to separate the walls from the new opening roof. This end panel goes closest to the garden shed and garage and faces East North East.

The aluminium rulers mark the roof runner position, while the two pieces of timber at the top of the picture show the top of the roof. The sides of the roof panels will be about 12 inches tall. The green foam tube represents the diameter of my 8 inch reflector telescope, positioned in the correct location in relation to the computerised mount. The front wall of the roof section will open upwards to allow the roof to slide down the tracks and clear the scopes. The walls however, are still tall enough to provide a wind break.

 

3rd~5th May 2022

The builders were repairing the cracked concrete in front of the shed and extending the area about four feet wider, including a ramp down onto the lawn. The first couple of days was digging out and packing hardcore in.



Day three was finishing the hardcore and pouring the concrete.

 

4th~6th May 2022

While the builders were working outside, I started assembling and cutting the first end panel.



A two inch square section timber was added to the top of the cut side, both to support the roof runner and to stiffen the two part end panel. The timber wasn't square, more of a parallelogram section, so needed quite a bit of planing to correct the shape.

 

8th May 2022

On Sunday 8th, I got back to working outside again. The outer floor joists were refitted and the diagonals carefully measured to get the base as square as possible. Once the position was set, I drilled the bolt holes into the footings for the rear corner leg brackets. The brackets were then bolted down finger tight and the floor joists screwed together. This was just a temporary measure. Once all the piers are done, I wanted to lay a weed membrane down over the footings and then bolt the brackets down onto them.

With the floor joists in position, the other six legs were marked up and cut to length. Their mounting plates weren't yet bolted down. With the frame supported and secure, I marked out the edges of the pier foundations on the timber frame and knocked some small panel pins in. String was then stretched across the pins, end to end and front to rear to give me the pier position.



Small stakes were then hammered into the ground where the string crossed to mark the area to dig.



Lynne supported the end wall for measurements, to double check the height of the top edge and to work out the pier foundations and pier heights. Her eye line is around the height of the top of the roll off roof. So many positions of things were all interconnected, with one dimension dependant on another unknown position. Floor height, wall height, roof height, pier foundation depth and pier height were all interconnected, so I spent a great deal of time measuring things over and over.

Due to the floor height above the lawn, I planned on making some steps for the doorway. When not in use, the steps stow inside the observatory and leave the lawn unobstructed for mowing.

Also done that day, the other end panel was trimmed and the roof runner timber screwed in place. The tongue and groove side was planed down to the runner and sanded flush.

 

9th May 2022

The day was mostly spent digging and digging and digging! The first pier hole was extended in width to match the strings plotted out the day before and then I started digging. Since the slope of the earth drops away where the pier is, I wanted to go down a decent distance so the foundation was supported on all sides. Stability of the pier is critical for astro-photography. The hole was about 2 feet square and a tight space to dig in, once I got too low to reach from the outside.



We got a second hand cement mixer, which made short work of mixing the concrete for the foundation at the bottom of the hole. Three layers of high density concrete blocks would be built up in a square pattern, with a hole down the centre. The centre of this square would be filled with more concrete and the space around the outside of the blocks and the hole would also be filled. Four re-bars are fitted up the centre of the square and a further four would extend up to the top of the pier tube.

 

10th May 2022

Because the pier height was related to the floor height, I wanted the floor frame assembled when I poured the main concrete of the pier foundation. To make that weather proof, as it may have been out a while, I painted the supports and joists in bitumen. They were left to dry and I went back to digging the second pier hole. All I can say is that I'm pleased I didn't dig this one first; otherwise, my observatory may have only had one pier!!

It was very hard going, with lots of smaller one to two inch stones or bits of brick in the upper layers. This meant my spade couldn't dig through it and I had to resort to a small gardening trowel, which due to its more pointed end, could cut between and push passed all these small stones. As I dug further, I started to find larger bricks and what I thought was a complete brick at first, turned out to be a five to six inch slab of very hard concrete, wedged under and over more bricks. More of the air raid shelter floor!



I had to mine under and around it before belting it with a small sledge hammer, breaking it up into four main chunks which still put up a fight to remove! The further I went down, the more large stones and bricks I found. My dodgy elbow was killing me.

By the time the school pick up run was due, the hole was almost at full depth, but it fought me all the way. Five full wheel barrows of heavy clay soil came out of the hole, along with this pile of bricks, concrete and stone. You can see a brick in the top centre of the pile to give scale to the lumps! I could barely lift the trowel by the end of the day.



My placing of the hole, dictated by the nearby tree stump, was fortunate. As I dug down, one edge of my hole fell exactly in line with one of the brick walls from the old air raid shelter ( inset ). These bricks are very hard and the wall is double brick thickness. When removing the bricks under the conifer hedge, I broke the shaft of one hammer and damaged another getting them out! So I'm really fortunate the edge of my hole was flush with this brickwork.

 

Oh my goodness, what a fascinating diary, thank you for sharing. Just the thing to read on a rainy afternoon, I’m feeling exhausted just doing that! I can imagine how annoying that concrete delivery was, and the shed delivery reminded me of when we had some large floor tiles on a pallet left half in the (very narrow) road on a bend, luckily the kitchen planner came immediately to help shift them as even a neighbour with a tractor couldn’t manoeuvre to the correct angle to shift it