Before I could install the plywood, I had discovered that the shed recesses were 40mm deep, but the polystyrene sheets are 50mm deep, so now the polystyrene is sticking out 10mm, so I could either cut down the polystyrene or pack out the frame by 10mm to bring it up level.

I decided to pack out the frame with pieces of plywood I cut up as well as free wood I managed to get from Travis Perkins.

Now I was ready to cut up the plywood and I panelled out the whole inside of the shed, including the inside of the door.

I also made some shutters for the window using some left over plywood and I then used more plywood to encase the surround of the base, where the pier will be going.

For my 8x6ft Pent Shed I could have done with 8 plywood sheets, but I did manage to complete the job with 7 sheets, but had to have one side of the shed wall made up of several cut pieces instead of using just one board.

Next comes painting the inside of the shed.

Related posts:

1. Insulating the Observatory Shed
2. Observatory Build – Putting up the Pent Shed
3. Observatory Build – Day 1 and 2
4. Observatory Build – Laying the Slabs
5. Completing the Observatory Roof