I saw the parasol yurt fort by Renard_Bleu and decided to try making one myself. It worked but needed some changes to the design, so I thought I'd put them here in case anyone else has the same situation.
His design is here - https://www.instructables.com/id/Parasol-Yurt-Fort/
The materials I used were about a metre of decking board, six inches of 2x2 and two woodscrews. The tools were a woodsaw, chisel, screwdriver, electric drill, woodcarving knife and some sandpaper.
Step 1: Terrain
Since my younger daughter loves tents and dens, I decided to try and make a parasol yurt for her. Due to my backyard being paved, I couldn't do it as the plan said however so had to make some changes. I added some pouches to the hem of the fort (an old sheet from a second-hand shop) to put weights in and a base to stand it up.
Step 2: Basic Design.
I thought that the easiest style to make would be an X shape with a tube from the top to hold the pole in. Since I had a length of decking board in my shed, I decided to use that. I used the grooves in the board as guide to saw it in half and sanded it down.
I didn't think to take a photo of this step until after the fact sadly, so this is a quick snap later in the process.
Step 3: Linking the Slats
As I wanted this to lie flat on the floor, I decided to cut slots out of the slats to link them together. I cut them with a saw, chunked out most of the wood with a chisel and smoothed off again with a knife.
Step 4: Pole Support.
I originally intended to attach a length of plastic pipe to the wood to hold the pole but had a few problems with this so instead decided to drill out some wood for it.
The pole is slightly thinner than a 25mm bit, so I used that to drill a "more or less" vertical hole through a 2x2 chunk of wood.
I then attached this to the slats with two screws, which also hold the slats together.
Step 5: Final Fixes
Once I'd finished the construction, I discovered that the parasol wobbled noticeably and drilled a 10mm hole into the slats. This gave the end of the pole somewhere to slot into and stabilised it quite nicely.
After this, I painted it with some wood protector so the different types of wood matched and that was finished.
The pouches by the way, were just squares of white fabric stitched into patch pockets around the base of the sheet. It should work for the beach too, instead of needing pegs, I can just stick some sand in them to hold the walls down.
I'll also point out that this wouldn't work for a regular parasol without a longer vertical support and possible longer slats. It's good enough for the fort as it's only about a metre tall and the backyard is fairly sheltered otherwise I'd worry about the wind toppling it.