Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: trcaw on July 01, 2012, 09:43:17 PM

Title: Ground/Concrete shifting under heater pics added
Post by: trcaw on July 01, 2012, 09:43:17 PM
We purchased our house (with a Hardy Heater already installed) 2 years ago.  The factory date on the heater is 2008 so it's not very old.  The heater sits on a concrete slab but it's gradually begun to lean due to the concrete below not holding up.  Does anyone have any experience with this?  Thinking about trying to jack up the heater and backfill with gravel or something to level it out rather than to have to pour another slab and move the pipes.  Any suggestions would be helpful. 
Title: Re: Ground/Concrete shifting under heater
Post by: Bull on July 02, 2012, 05:24:08 AM
Can you dig around the slab and jack it up and fill under it with sand? Pictures may help with ideas.

Welcome to the site
Title: Re: Ground/Concrete shifting under heater
Post by: AirForcePOL on July 02, 2012, 07:49:16 AM
yea post some pictures if you can so we can get some ideas.
Title: Re: Ground/Concrete shifting under heater pics added
Post by: trcaw on July 02, 2012, 09:50:39 AM
I'm not sure why the picture above is sideways...it's not on the computer or when you click the link below the picture.  Here is another (ignore my finger in the pic):
Title: Re: Ground/Concrete shifting under heater pics added
Post by: vagabonddreamer on July 02, 2012, 10:02:17 AM
how much settlement are we talking here??  depending on ground conditions below the slab, the shifting may take place for a few years...you might look at cutting pressure treated plywood squares of different thicknesses and place under the legs...pressure treated cedar shingles are also available for final adjustment depending on how particular you are about things being dead level...vs
Title: Re: Ground/Concrete shifting under heater pics added
Post by: AirForcePOL on July 02, 2012, 12:52:44 PM
Would you be able to drain the boiler (maybe even take it off of the slab) and then lift the slab up with the help of some buddies and have them throw some paver base or sand underneath it?  If that stove is empty you should be able to wiggle it off the edge of the slab and you shouldnt have much trouble getting it back on with some help.  I would stay away from putting wedges or anything under the Hardy because the entire bottom of it is basically the legs and that could cause too much pressure at one point and could dent the bottom of the stove.
Title: Re: Ground/Concrete shifting under heater pics added
Post by: jerkash on July 02, 2012, 06:32:15 PM
If it were mine and I didn't have any machinery cabable of picking it up, I would drain out all the water and unhook all lines and get two 4"x6"x6'.  You could jack up each end and place a 4x6 under each end.  Once they are under the heater, continue to jack up each end 6" or so at the time and put blocks under the 4X6's on the ends until you get it a foot or so off the ground.  It will be easier to bust up the old concrete and start over.  Place a layer of rock down and pack the best way you can and then pour another slab and then set the heater back down just like you lifted it up. 
Title: Re: Ground/Concrete shifting under heater pics added
Post by: Bull on July 03, 2012, 03:44:42 AM
It is kinda of hard to tell how far off it is with the form being off that much. I would take the form off and check with a 4 foot level to see how much it is and if less than 1 inch in that 4 foot I would not worry about it to much but keep an eye on it. If more than an inch dig to the bottom of the low side of the concrete and jack it up and tamp sand under it. 
Title: Re: Ground/Concrete shifting under heater pics added
Post by: muffin on July 03, 2012, 07:40:01 AM
Just out of curiosity, if the concrete pad is shifting, doesn't that mean the base was not prepared correctly prior to pouring.  So trying to fill under the slab would have little affect as it will just settle again.  Seems like they must have poured on fill or something instead of digging to make it level.

I agree that if it is only an inch I would not worry about it.

Otherwise your best bet may be to try and lift the furnace up and perhaps dig a footer trench under the side that is sagging.  You could jack it back up to flat and try to pack the ground as best as possible under it and then pour/fill the trench.  That would get that edge back on stable ground.

Hopefully you have something to lift it with.  I had a heck of a time with mine.  Had to borrow a friends tractor and it still could barely do the job.
Title: Re: Ground/Concrete shifting under heater pics added
Post by: hpowers on July 03, 2012, 10:30:11 AM
been in concrete business 20 years, only way to fix it properly is bust it out and put 3" of either 3/4 clean or ca-6 and compact it then re-pour your pad
Title: Re: Ground/Concrete shifting under heater pics added
Post by: johnybcold on July 03, 2012, 02:53:04 PM
I would be tempted to try and jack it up with a cheap harbor freight jack,
Title: Re: Ground/Concrete shifting under heater pics added
Post by: Bull on July 04, 2012, 08:15:14 AM
I would be tempted to try and jack it up with a cheap harbor freight jack,

or an old style bumper jack