1/2 in. x 2 ft. x 4ft. Medium Density Fiberboard

MDF will absorb water and moisture if it becomes wet when untreated. Though denser, it will react much like particleboard. From your question I am not sure if you are using it in a garage or storing it. If you are using it for construction, then it needs to be sealed with paint or something else so it won't absorb moisture. If you are storing it, I would only do so for a short period of time.

Yes, MDF will deteriorate over time if exposed to moisture. I would seal the wood somehow, to prevent it from absorbing the moisture. Paint, or poly, etc.

No it was not! Not for me! Just bought five of these tonight and they were larger than 2ft x 4ft. It actually ended up being 24.5” x 48.5”. Will be returning tomorrow. Like the previous poster said, bring a measuring tape and measure!!

I have that board as a table top for my scroll saw, to be sure I went out and measured it. As I expected it was perfectly 24 inches by 48 inches. Unlike natural woods MDF is normally made to precise measurements. To be sure you can do what I do when I go get wood products, take a measuring tape with me.

Yes, the actual dimensions are 24'' x 48''.

This 2' X 4' medium density fiber board weighs about 8-10 pounds. It weighs a few pounds more than a typical piece of plywood of the same size. It should work for your intended use as long as it is screwed into ceiling joists properly and securely.

Though I dont exactly know the weight it is heavier than a sheet of plywood. It is very dense, I myself would be leery of attaching it to the ceiling. I used it for a tabletop for my radial arm saw. I would if you are going to try just start with one 2 x 4 sheet. Sorry I couldn't help you anymore.

Will not allow any type of pins.

This is a wood based product so it will char if the heat is high enough. Push pins would not be able to push into MDF, it is too dense.

yes

If you get it in the store you can have it cut to those dimensions but if you order online you will get the full sheet

You can use a saw with a wood cutting blade to cut this board.

Yes, you can cut it

My guess cutting the board will not effect it's strength, they have already been cut down from a 4' x '8 size.

It is too high density to easily push thumb tacks into it. The best tackboard is actually made from compressed fiberglass and then coated with fabric. The other product is something like a product known as "homasote". Tackboard would probably called low density fiberboard.

This product is made from pressed fiber board. It would not make a suitable bulletin board material.

You can use any type of saw with a blade designed to cut wood.

circular saw

I've used a zigsaw and a circular saw to chop down the size of these boards without any problems, my guess would be pretty much any saw you can cut down a piece of plywood, would work on these. Wear a mask and use eye protection.