Cement pad/slab thickness under boiler
PatchogPhil
| Posted in Construction Techniques on
(I had a link to this information, but somehow misplaced it…….)
How thick should the cement pad/slab be that is under a residential boiler? The cement pad/slab that is presently under my boiler is collapsing and sinking on one side. The boiler now lists and it is putting strain on the pipes.
So, I’m gonna bust up whats there, figure out why it has sunk, and pour a new slab after leveling and compacting.
Any tips? Should I put in some rebar?
TIA
Phil
Replies
a normal 4" slab with rewire in should do it. Sounds to me like yours is only an inch or so thick and has water washout voids under it. A boilker insn't heavy enough to cause that you describe.
You're right about the boiler not heavy enough to cause the sinking by itself. I suspect that scraps of wood were thrown down before the pad was poured. If so the wood has rotted away or been eaten by termites. And that area has been flooded out twice in last 8 years, once by a cracked boiler in a severe 0* freeze and another time when the whole-house water filter housing cracked open on the 3/4" water main.
Well, whatever the reasons for the failure, I'll rebuild it and I want to do it right.
How long should I wait before I put the boiler back on the new 4" pad?
Thanx,
Phil
I'd wait a week or more to set the boiler on the pad.
Lots of variables but three days should do. Weak mix in cold temps might take a week. Strong mix cured warm with plastic over could do in thirty hours well.Excellence is its own reward!