Seal a Gaping Hole With a Leaking Inner Tube

The inspiration for this instructable came when our porch began settling leaving a gaping crack between the porch and the house.  An entrance to the basement sits below the porch and when we get a heavy rain water would come in.

The idea is to cut a length of the inner tube with the valve still on it that will run the entire length of the crack, seal the ends, insert the tube into the crack, inflate the inner tube to seal the crack.  The rubber is pliable enough to expand into all the nooks and crannies as long as you inflate it with enough pressure.  The higher the pressure in the inner tube, the higher the water pressure (or taller the head of water) it will be able to seal against.

I haven't gotten a chance to test this on the porch but here is a little experiment I did to test the concept...

Step 1: Materials

You will need the following materials
-inner tube
-needle and thread
-multi-tool (always handy)
-air pump
-solvent based glue

Step 2: The Hole

To test my theory I cut a wide crack into a bottle of fabric softener, as pictured.  Your first step will be to cut a piece of the inner tube around the valve about the length of the crack + about 1/2 an inch extra on each end. 

Step 3: Wash Out the Tube

If you are going to use a glue to seal the ends you will want to thoroughly wash the inside of the tube out in order to get a good seal.

Step 4: Seal the Ends

I originally tried to glue the ends, but the only glue I had was a two par epoxy without a solvent so it didn't bond well.  Instead I opted to sew the end of the tube shut to see if I could at least get a prototype working.

It is important to fold the end of the inner tube over as this fold is actually the seal; the stitching is just to keep it fold in place.  

PICTURE 1
Start sewing by pushing the needle through the fold as seen in the first picture.  This may be a little tough so keep a thimble or folded up piece of paper at hand;  a pair of pliers from the multi-tool also came in handy.

PICTURE 2
Loop the thread around the side of the fold (not over the top) as you push the needle back through to the first side.  As seen in picture two, stop before the needle goes all the way through.  Use the trailing end of the thread (the piece thats on the side of the tube w/ the business end of the needle) and wrap it around the needle 3 or more times.  Then pull the needle the rest of the way through;  This will create a knot and allow you to seal the outer most edge of the fold.

PICTURE 3
Now proceed across the fold to the other end of the tube, going over and under as seen in picture 3. When you get to the other end repeat the knot you used to start the process.

Step 5: Seal the Crack

When both ends of the inner tube are sealed, insert it into the crack.  Make sure that you fold each end of the inner tube over again (as seen in the picture) so that one side of the stitching contacts one side of the crack and the other side of the stitching is against the length portion of the inner tube.  If you forget to fold it over one more time on each side the ends of your crack won't be sealed because the inner tube won't be able to expand out in past the stitching into the ends of the crack.

Once the tube-patch is in place in your crack, inflate it through the exposed valve to about 15 psi, or as high as you dare.  In theory 15 psi is enough to seal a crack at the bottom of a 30 foot pool, assuming that your folds and seams are cut pretty well.  In reality I would probably only trust it to seal about 10 ft of water, but the higher the pressure your seals can take the better your tube will protect against leaks.

RESULTS:
The patch worked, but only while I kept pumping air into the tube.  AKA, my stitching wasn't enough to seal the inner tube at the required pressure.  I will have to get a solvent based glue for the real application.  I will however still stitch the ends as I don't think the glue alone will hold up to the pressure either.