I built a similar sandbox several years ago. The only real difference is that I had a seat on all four sides. I built mine with 2 2X8s on each side and used another 2X8 for the seat. I used 2X4's in the corners and set the 2X4's about 12" down into the soil. The geofabric will do a real good job for you in keeping the sand from mixing with the soil below.
A tarp is a good idea - especially to keep the cats out. We forgot to put the tarp on a few times and it was used as a litterbox.
We now have a tractor tire sand-box and this has also worked well for us and was less work to install.
Insted of the treated lumber I would use some other rot resistant wood. Treated lumber has some nasty cems in it, I don't know if I would want kids playing with it. Over here I would use Ceader, but I am sure you have some natral rot resistant wood of your own over there. Just my thoughts....
<font color="blue">Insted of the treated lumber I would use some other rot resistant wood. Treated lumber has some nasty cems in it, I don't know if I would want kids playing with it. </font color>
This was a source of much excitement at a recent town meeting regarding the local playground. After consulting many experts, the decision was to seal the wood using polyurethane. Added benefit: Reduced the amount of splinters. I'd use a marine grade poly as it is an outdoor application.
I'd say you have a good plan and it should be a nice setup for the kids. I used treated lumber and it's over 3 years old now and the kids have not contracted any sickness. I think people worry too much about that. I read that a kid would have to chew on the wood for 50 years or something to have any effect. As for the tarp, make sure it's fastened down tight all the way around or cats will find a way in, as mine did. They will find a loose spot, and it doesn't take much. I had to replace all the sand and then I made a top out of plywood, which isn't working out too good because it's too heavy to get on and off.
What about the sand? I got fine sand (I got a pickup load for less than $10) the first time and it was real good because it packed together when it was wet so the kids could make sand castles and stuff. The second time I got talked into getting a coarser sand (with very small stones) and it dries out quicker, but it won't pack near as good and the kids don't seem to like it. I'm planning to bag it up and make some sandbags (which I've been needing for weight in my 2WD pickup in the winter anyway) and replace it, for the 3rd time, with the fine sand again.
A lid - Yes. But to keep put the frogs not the cats. Have only ever spied one cat around here but not in our yard.
The sand I bought for the yard was medium sand and did have little stones in it. Sonny seemed happy to play in it before I spread it, but yes, the fine stuff looked nicer.
We took the tractor, and dug a pit about a foot deep, and eight feet across. Then, I got about a couple yards of playground sand and dumped it in there. This was right before our son's 7th birthday.
Then, we buried dinosaur toys in the sand. We got one of those wood skeletons, and hid the pieces in the sand. When the party started, part of it was to dig up treasures in the sand(I came up with a corny story about doing tractor work out there, and making an amazing discovery...) When they found the wood skeleton parts, they had to assemble it to make the dinosaur.
They loved it!
Amazingly that was 1.5 years ago, and the cat has steered clear. There is plent of sand still, along with some good dirt,, and since it rained, a bit of mud. What more could an eight year old kid want [img]/forums/images/icons/ooo.gif[/img]
I don't know what type of sand is available, but my dad always used mason's sand for our box. The sand that is sold around here as "play sand" is washed and very "soft" to the touch, but the granules are round and won't form well into castles, moats, mountains, etc. The mason's sand has grains with angular surfaces, and it packs well and maintains its shape when moist.
We used to build "Toad Towns". Twelve kids would scour the neighborhood for toads, then build towns and buildings for them. We might have 60-70 toads at a time. At the end of the day each kid would take the toads home and release them - until the next Toad Town day. Nowadays I rarely see toads.
They were introduced to eat sugar cane beetles. They didn't do that but bred out of control. Nothing eats them and they are poisonous to all out native animals.