Replacing select rocks from river rock hearth

[SKJ]

We just removed an old wood stove from a river rock hearth. Our new wood stove has a different footprint than the old stove. Before we can install the new stove, we plan to chisel out the existing rocks where the four legs of the new stone will sit and replace them with flat river rock. This is a DIY project because we couldn’t find any professionals who would take on such a small job. We could use any suggestions to help us do the job right ourselves. Here’s a photo showing a paper template where the new stove will fit on the hearth. Thank you.

 

[Highbeam]

I never liked a hearth made of round rocks because of this issue and difficulty in cleaning.

Rather than chunk out entire stones, how about just grinding down the stones as needed where needed to accommodate the 4 feet of the stove. A 10$ angle grinder with a cup but from Home Depot will mill that stone right down. The milled stone will look different so you can paint it black, Grey, or nothing.

 

[EbS-P]

My cup grinding experience while limited is enough to know it’s harder than it looks like it would be to control. Does your new stove have a leveling kit or mobile home compatible? I ask because it might be easier to to drill holes (exact locations will be necessary) and epoxy threaded rod into the holes then bolt the stove legs to the threaded rod. It would be very adjustable vertically and all that’s left would be a painted trim piece to hide the rods. Not to mention much much cleaner. Could be a real pain to get stove on bolts and everything lined up. Cup grinders are messy.

just my thoughts

evan

 

[SKJ]

My cup grinding experience while limited is enough to know it’s harder than it looks like it would be to control. Does your new stove have a leveling kit or mobile home compatible? I ask because it might be easier to to drill holes (exact locations will be necessary) and epoxy threaded rod into the holes then bolt the stove legs to the threaded rod. It would be very adjustable vertically and all that’s left would be a painted trim piece to hide the rods. Not to mention much much cleaner. Could be a real pain to get stove on bolts and everything lined up. Cup grinders are messy.

just my thoughts

evan

We can’t get exact locations to do what you suggest because we need a little space to adjust the position of the stove to the existing pipe. I asked the guy who’s helping us about grinding, and because of the mess it causes he wants to try chiseling out the four+ rocks where the legs will sit before we resort to grinding. But I appreciate these suggestions. Any tips on chiseling? Any tips on laying the new flat rocks so they are as close as possible to level.

A stone mason told us we need a very good chisel and a three pound hammer. And to cover the windows with cardboard.

 

[Supersurvey]

Drill some holes in the rocks first?

 

[brenndatomu]

I think I'd just set the new stove on a sheet of 1/4" steel plate, done. Easy to shim under the plate as needed to be level/stable...paint it flat black or whatever color you want.
If you want to cut flat spots out for the feet to sit you could use a masonry hole saw to cut the core and then a chisel to snap it off...or just call a concrete cutting service to do it...they deal with it all the time, and by the time you buy a diamond hole saw/etc, it may not be much more to hire it done...but I'd still lean toward using the sheet metal.

 

[SKJ]

Drill some holes in the rocks first?

I think I'd just set the new stove on a sheet of 1/4" steel plate, done. Easy to shim under the plate as needed to be level/stable...paint it flat black or whatever color you want.
If you want to cut flat spots out for the feet to sit you could use a masonry hole saw to cut the core and then a chisel to snap it off...or just call a concrete cutting service to do it...they deal with it all the time, and by the time you buy a diamond hole saw/etc, it may not be much more to hire it done...but I'd still lean toward using the sheet metal.

The rocks are way too uneven to do a steel plate.

 

[Silversniper]

Its a tricky job. I have used a grinding cup with success and favour grinding over chiselling as it is more controllable.

Have you thought about going up rather than down- using a small pad of high strength masonry grout as a shim under each leg? There may be a product available e.g.http://www.mortargroutepoxy.com.au/highest-strength.html

 

[Highbeam]

How would removing a rock and putting in a new one solve anything? Those look like manufactured “cultured” river rocks. Those rocks are lightweight concrete and should chip away pretty easily. Hammer drill, mini demolition hammer, air hammer, or manual hammer and chisel would work but be a mess and leave you with something that needs a cup grinder anyway. Then your plan is to mud 4 new rocks in?

 

[SKJ]

How would removing a rock and putting in a new one solve anything? Those look like manufactured “cultured” river rocks. Those rocks are lightweight concrete and should chip away pretty easily. Hammer drill, mini demolition hammer, air hammer, or manual hammer and chisel would work but be a mess and leave you with something that needs a cup grinder anyway. Then your plan is to mud 4 new rocks in?

We are amateurs forced to do the work because no professionals have expressed interest in doing what they see as a small job in a remote mountain community. The original stove sat on four flat river rocks. The rest of the rocks are rounded. How can you tell the rock is manufactured? The hearth was laid in 1977.

 

[Bad LP]

Make a round form out of a mailing tube, fit and pour an agreeable material where the legs will be.

 

[brenndatomu]

The rocks are way too uneven to do a steel plate.

Guarantee they are not...you lay the plate down, level it, and then "shim" it as needed.
But I also like the above idea too ^ ^ ^

 

[Silversniper]

Or, use four small steel squares 4”x4” each supported by a bed of construction grout.

 

[SKJ]

Or, use four small steel squares 4”x4” each supported by a bed of construction grout.

Where can I find those squares?

 

[Silversniper]

You can make them from a piece of steel plate of whatever thickness you desire. Just chop it into four squares.

Or, just ask at a metal shop they often stock pieces like that exactly for this type of job.

 

[Silversniper]

Here is what I am suggesting - but in a smaller scale https://www.uk.weber/technical-mortars/grouting-steel-baseplates

 

[brenndatomu]

The rocks are way too uneven to do a steel plate.

Or you could make a nice flat grout base to set the steel plate on...kind of a combo of what I was thinking earlier, and what @Silversniper is suggesting.

 

[Prof]

Grinding with a shop vac being held near the wheel will create little to no dust. Wetting things a bit would help out. Until you get the stove where it needs to be it will be difficult to know what needs knocked down or raised for that matter.

 

[Highbeam]

You don’t know for sure if they are real or cultured but being that old are more likely real.

Removing stones and putting in new ones is not the solution. Even if you had flatter stones you would need all perfectly the same elevation and that’s not reasonable.

The stove is there. Have you tried it? You need to do it to mark the feet locations and to know what feet spots need to come down. I would prefer all four feet set on a milled flat spot.

Get an angle grinder and a cup bit and start shaving down the stones. It’s easy. I’ve ground down lots of cured concrete. This is fastest and cheapest. Burn season is coming.

Crazy thought but you could just mix up a big bucket of mud and dump it on the hearth and screed the whole thing flat as a base for proper tile or pavers. You’re not stuck with those cobbles for a hearth.

 

[coaly]

I use a diamond wheel on an angle grinder like used for tile. Very smooth precise cuts, and have someone keep it wet with a spray bottle to keep dust down.
Set stove in place, Shim level with washers so you know exactly where it will be. I use painters tape to make lines on the hearth straight out from the legs forward and back, and sideways about 6 inches long from leg outward. This gives you 4 crosses where you need to grind with stove removed. The tape stays in place so you don’t loose your marks.

I have a laser level on tripod to get the correct level, but you can set the same thickness shim at each corner and set level on shim to lower each one to the same elevation.

 

[Keith E Cantrell]

Using a diamond wheel is seems like a good idea.

 

[Highbeam]

What are you all calling a diamond wheel? The cup bit is a diamond wheel also but they also make discs with diamond grit for cutting. The OP is new to this.

The reason I like the cup bit for leveling the floor is that you hold the grinder horizontally with the handle and you cut a larger area at once for more control and smoother results. A highly skilled operator could do the same thing with a cut off disc but the cuttings are thrown up in the air.

 

[SKJ]

You don’t know for sure if they are real or cultured but being that old are more likely real.

Removing stones and putting in new ones is not the solution. Even if you had flatter stones you would need all perfectly the same elevation and that’s not reasonable.

The stove is there. Have you tried it? You need to do it to mark the feet locations and to know what feet spots need to come down. I would prefer all four feet set on a milled flat spot.

Get an angle grinder and a cup bit and start shaving down the stones. It’s easy. I’ve ground down lots of cured concrete. This is fastest and cheapest. Burn season is coming.

Crazy thought but you could just mix up a big bucket of mud and dump it on the hearth and screed the whole thing flat as a base for proper tile or pavers. You’re not stuck with those cobbles for a hearth.

You seem knowledgeable. Are you in the business?

 

[brenndatomu]

A highly skilled operator could do the same thing with a cut off disc but the cuttings are thrown up in the air.

Except its going to be impossible to make things flat/level/smooth due to the other rocks sticking up all around where you are trying to cut down in...could maybe cut some chunks out with a diamond blade and then level/smooth things out with a diamond cup...personally, I really think I'd just grout some little steel platforms for the legs to sit on, or do the same thing with a stove size steel plate...

 

[coaly]

What are you all calling a diamond wheel? The cup bit is a diamond wheel also but they also make discs with diamond grit for cutting. The OP is new to this.

The reason I like the cup bit for leveling the floor is that you hold the grinder horizontally with the handle and you cut a larger area at once for more control and smoother results. A highly skilled operator could do the same thing with a cut off disc but the cuttings are thrown up in the air.

A flat disc. I use it for cutting brick, block, stone, rebar. Notching stone I cut a series of slots and chisel across the cuts. Then dress it with the disc edge if large enough to get the wheel in. Don’t know if they make a diamond blade for a multi tool. That would flush cut into corners nice.