Our barn roof has a center ridge board that gives us a great place to push on to raise the roof, but that ridge board is 16 1/2 feet above the haymow floor. After talking with a local carpenter we decided to go ahead and place the jacks on the haymow floor after using bridge planks to spread the load. Additionally we identified where each jack is and cut and jammed a post under the floor to transfer the load to the concrete ground floor. We now have a direct load path from the jack to the ground.

Once the bridge planks were laid up and we had the jacks in place we measured 14 foot 3 inches from the jack to the ridge.

We purchased 4 - 14 foot 2 x 4's for each post and screwed them together with 3 1/2 inch screws to form a 3 1/2 x 6 1/2 box. We did this so the grain of the wood was alternated and we had less concern about the posts bending under load. We also were able to align and adjust the 2x's as we screwed them together to get a very straight post. Try finding a 14 foot 4 x4 or 4 x6 at the lumber yard that is straight.. (Small Photo inserted lower right)

Each post then had a 2x4 installed on the bottom along with a steel plate that rests on the jack. These help distribute the load and also prevent the jack from crushing into the wood. (Small Photo inserted lower Left)

Each post was lifted up on top of the jack and raised up against the ridge until snub with the jack. We plumbed each post in both directions. One thing we could have done to make this safer was to attach the top of the post to the ridge. We had a couple of situations where when we raised one jack the others became loose and the posts moved.

Out of our available stash of bottle jacks we used 1 - 20 ton and 2 - 12 ton jacks. These were by far larger than they needed to be. We could have gotten by with 2 or 4 ton jacks. The 20 ton was under the center post and perceived to have the largest load, but we could pump it without using the handle, just our fingers could operate it.