gas pipework chased into the plaster work is fine. Copper is fine if protected from corrosion. It only needs a steel plate (1mm thick) fitted over it if its chased into the brickwork its full depth. The gas pipe will need to be incased in either sand and cement or dabb. There are drawings in the corgi and viper books showing how its done.
Personally i would try your best to avoid it as its alot of work and if you want to alter anything later it will be a pain. Can you get a stand off kit for the boiler and drop down from above?
remember to make sure if you go into the brick/block work you keep the chase depth to the building regs to avoid weakening the wall.
if its a newly dabbed wall you could consider cutting out the plasterboard, sealing the sides and running the pipework clipped to the brickwork and the above the worktop create a removable box under the boiler which you could tile over to match the wall, just remember to seal both side of the timber box before tiling to avoid it bowing.
Personally i would try your best to avoid it as its alot of work and if you want to alter anything later it will be a pain. Can you get a stand off kit for the boiler and drop down from above?
remember to make sure if you go into the brick/block work you keep the chase depth to the building regs to avoid weakening the wall.
if its a newly dabbed wall you could consider cutting out the plasterboard, sealing the sides and running the pipework clipped to the brickwork and the above the worktop create a removable box under the boiler which you could tile over to match the wall, just remember to seal both side of the timber box before tiling to avoid it bowing.
