Stone sealer

Do you want matte or gloss finish?

 

I haven't been on here in a while, but I do this for a living. I'm not entirely sure what orchard stone is, but if you want to post a couple pics I can help.

 

That's a sandstone. Silica based (non-reactive to most acids) and extremely porous. I would avoid any topical or finish sealers on this. Moisture can travel from underneath the slab, from the surrounding irrigation and wick up through the body of the stone and start to deteriorate the sealer. An impregnating sealer is what you want. It will penetrate into the stone and protect it from within, but will not alter the finish.

Prosoco SLX 100 is the best sealer for this, IMO. It is a sealer designed specifically for concrete and silica based stones, like granite, sandstone, quartz, etc.

The SLX 100 has a strong odor, but dissipates quickly. The nice thing is that you can spray it on with a cone tipped sprayer ($35 bug sprayer from Home Depot) and leave it. it won't leave a residue.

I would do at least 3 thorough coats, if not one or two extra. You must let the stone dry and return to it's natural color before doing any additional applications to maximize efficiency.

I can't stress enough to stay away from "sealers' Or anything that is designed to be a finish, or change the finish. impregnating sealer only.

Here is the product info on Prosoco SLX 100
PROSOCO, Inc.

Technical Data
http://www.prosoco.com/Content/Documents/Product/SO_SLX100%20_Water_Oil_Repellent_PDS_052313_C.pdf

They do not sell direct, you'll have to find a distributor. White Cap and Sunshine Supply are the only ones I know off the top of my head, but they have a distributor locator at the top right of the product page.

I would account for 200-250 square feet per quart per application. So 3 applications would be 3 quarts per 200-250. This may be a bit exaggerated, but it's better to have extra to use for next time, than run out in the middle of the job.

 

These are some interlocking pavers I sealed. They have a similar porosity to your orchard stone. This is what a good sealer will do

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTOh41amsehBQkHHyoxkwcEG0WzcxORVLboVgKooU8LpkK7YC-D