This is a relatively simple way to update a kitchen by adding a new timber benchtop, without the trouble of removing the old one.
You can watch the project video on YouTube: https://www.youtube.com/watch?v=nVZWBLSZCzE
Step 1: Measure the Existing Countertop
I was recently asked by a friend to help update his kitchen. The melamine benchtop had cracked and chipped and he wanted to bring it up to date by changing it to a wood countertop. Instead of removing the old one I simply installed the new one over the top of the existing one. This would speed up the project but also raise the already low benchtop.
Most countertops are roughly the same depth (this is to accomodate the cabinets makers, appliance manufacturers, etc) so if you were installing a square or rectangular benchtop this would be a simple case of buying a prefab one from the store and cutting it to length. In my case I had a corner to deal with and decided to go with a mitre join.
I started by measuring the existing countertop. Be sure to add a small overhang so that you can cover the existing benchtop. I extended mine by roughly 30cm.
Step 2: Cut the New Wood Countertop
Transfer the measurements onto the store bought benchtop. This was roughly $100 AUD at my local big box store, but I've seen them even cheaper.
Using a circular saw and a piece of wood as a guide, I cut the benchtop to length. Here you can see the mitre (or 45 degree) cut that I created with the 2 pieces.
Step 3: Prep the Old Countertop
Next you need to "key" the surface. You can do this with a knife or sandpaper. All you're doing is creating small indents for the glue to lock into. Melamine is notoriously smooth and slippery so glue won't stick to it. Doing this ensures a good bond
Step 4: Attach the New Countertop
Now you can add the construction adhesive. Add a liberal amount because this is going to have to hold the timber in place, but it also fills any voids if the surface is slightly uneven.
As a general rule timber will move with seasonal changes. In most cases you need to allow for this but with this method we aren't allowing the countertop to move at all. This is fine provided to use enough "fasteners" to stop it from moving. Because this kitchen is indoors it will only be slightly affected by seasonal changes, but you still need to make sure there is as much glue applied as possible (without putting on so much that it squeezes out everywhere).
Place the new counter top into the bed of construction adhesive.
While holding the countertop in place, add screws from below, through the existing bench. I had a friend help apply pressure from the top, but you could also use clamps. This is important to make sure the new bench doesn't move as you drill, but it also squeezes the glue into the 2 surfaces.
Step 5: Apply Finish and You're Done
Once the glue has dried you can sand the counter if needed and apply finish if it wasn't pre-finished.
And there it is! Now I just have to finish the rest of the kitchen.