Hi, did this quite a few months ago but thought I'd share as it may help someone with ideas.
When we bought the house, it needed a lot more work than we thought, and this was part of it. This may seem a simple idea, but sometimes simple gets over looked. We decided that the old gas fire had to go completely, but obviously you may wish to keep. This was the old when we first moved in.
So it had to go!
Had a gas man come out (JJ Rowney if you are in the Doncaster area), to remove the fire and cap the gas pipe. Purchased a reclaimed oak beam, was originally painted white. This was cut to size and sanded back.
Having attached the 3 pieces together using flat L brackets, managed a test fit.
The original hearth has been left in place, saw no reason to make a new one. Plaster board fitted to the sides, top and rear.
Numerous coats of wax was applied to the wood before bracketing it to the wall. Decided to fit the brackets before tiling so they were hidden. This may not be agreed by everyone in case it needs removing, but I'll take that chance as it looks better. Tiles applied to the back and sides, the top was painted (you don't see that bit!), and tiled straight on to the hearth after sanding it to rough up the surface.
And so this was the finished item
What do you think? Hope you get some inspiration from this site.