Which is better - gunite or shotcrete?

Answer 1

• Ask any structural engineer, when strength factors are to be recognized shotcrete is required. Gunite companies cannot guarantee their product to 2500 psi. Just ask one to put that in writing. Our shotcrete product is an engineered mix from the plant at a min of 4000psi. We can get an engineered design mix at 7500 psi if we need it. And yes, shotcrete has rock in it for structural strength. Gunite being man mixed at site has much more margin for error. Both are applied by air pressure. Gunite pools will lose their finish sooner and are more prone to crack because of lack of strength integrity. Simple test for those in question, take a mason drill bit or air chisel to Gunite and then Shotcrete and see which is less resistant. For the Shotcrete test bring a lunch, you'll be there a while!

• Gunite and Shotcrete are the same thing. They are both a force applied concrete application. The difference between Gunite and Shotcrete is this: one is concrete mixed with water at the site (Gunite) and the other is concrete mixed with water in a truck and then brought to the site (Shotcrete)

• One has aggregate in it and the other has none the aggregate strengthens the cement. Cement for other things like bridge's and road's has rock to make it stronger. Shotcrete is concretehas ,Gunite is not.

• Gunite is a nick name for shotcrete there are 2 kinds wet mix and dry mix dry mix is mixed at the nozzole wet mix comes wet and has rocks in it among other things to make it stronger for the frost we get in the mid-west gunite is the nick name of the first wet mix crew in 1942 during the war a man who owned the gunite gun smith shop invented the first shotcrete-wet mix nozzle when the air strips got shot up to keep our plains on the ground the gunite crew would spray and cut the air field in no time at all this is documented and i have seen pic of the first gunite crew i spray shotcrete-wet mix which is a lot stronger than shotcrete-dry mix.

• If there are no rocks in a wet mix the sand will dry pack in the hose causing a LONG day. Rock is needed to help float the material on pumping applications over 125 feet.

• I think both have there strong and weak points. The Dry process (Gunite) is a mixture of mainly sand and cement. The dry process is shot though the hoses like a sand blast operation with the water being applied at the very end of the hose.But when applied to a pool the crews mainly do the floors first due to the large amount of rebound produced. When the walls, benches , spas are shot the crews must throw out the rebound . The wet process which is a mixture of sand, cement, small pea gravel and water produces little or no rebound so the walls are applied first then the floor shot last.The wet process is brought out by cement truck and pumped with a small concrete pump then the air is applied at the very end to spray the material in place. All excess material pulled from walls are pulled in floor area and then shot over. This can't be done with the dry process. On the other hand during the summer months the dry process has an advantage as the wet process has a limited time to place and finish from the time of being batched at the concrete plant. The dry process is mixed on the job site allowing more time to work. I personally prefer the wet process as there is less equipment involved and I believe a more consistent product is produced.

• For a helpful discourse on the difference between gunite or shotcrete check out this web page http://www.monolithic.com/construction/shotcrete_gunite This site no longer exists.

• Do NOT let there be confusion between the two. SHOTCRETE is DIFFERENT from GUNITE. There was a recent legal action that forced shotcrete companies claiming they were Gunite, to remove all references to Gunite from their work. Any Engineer that knows these two applications will tell you the difference.

• GUNITE is a dry mix of sand and cement blow through a hose, water is added at the nozzle. as the material comes out, you have complete control over the water content, you can make it as dry or wet as you want. you add just enough water to make the material sticky (MUCH less water than a normal, if you tried to pump this material, you would probably blow up your pump. the material is moving at a high rate of speed as it comes out of the hose, the trickle of water doesn't even slow it down. Resulting in a higher PSI application, packing material tighter than Shotcrete can. Since you can make this material as dry as you want, you can achieve the strongest known form of concrete.
• Gunite is used on the space shuttle launch pad. each time a shuttle is launched, they must re-apply more gunite. it seems to crystallize. If you used shotcrete, it would melt and disintegrate. (they've done it).

  There is NO Wet/Dry mix gunite... if it comes out of the truck WET, it's shotcrete. if it comes out of the truck DRY, it's GUNITE.

  Shotcrete has less waste (rebound). Gunite has MORE waste (rebound).

  If it doesn't stick, THROW it OUT... if you pull this rebound into your floor, it will eventually crack up. REBOUND is BAD MATERIAL! trowel it into your floor, then pressure wash it, watch it come out like sand pockets.

  I have been doing Gunite for over 4 years, under a family of Gunite/Shotcrete work. they knowt he differences, and apply them accordingly. The family has been doing Gunite and Shotcrete for well over 50 years.

  If you spray gunite on glass, and let it cure, you will NOT get it off, you'll break the glass first. I, personally, would build no pool, other than a Gunite pool. Gunite pools will net you 90-100% of your investment in Appraising. Shotcrete 70-75% Pools: liners, fiberglass, fiberglass with concrete floors, etc, only 30-40% return on investment.

  Please do not confuse the two, GUNITE is stronger. the only thing that would make gunite or shotcrete crack up, is bad nozzling techniques. (get a reputable company, view their work before it is plastered or covered with whatever materials used) if it doesn't look perfect/near perfect, find another company.

• Gunite, Drymix, is dispatched in a cement truck just like wet mix, except that no water is added. This eliminates that "extra equipment" required.

  It CAN be mixed by hand from a pile of cement and a pile of sand, but all that shoveling, the labor, the mixer, CLEANUP, (i hate cleanup). We use the cement truck.. MUCH less messy. For a LONG time, it was just My boss and I doing the work. maximum crew required is 4, minimum 2. plus the truck driver to maintain flow of material into the Reed Machine.

• Another thing: When you shoot a pool, using Shotcrete OR Gunite... you shoot the FLOOR FIRST... THEN you shoot the walls. ALL rebound must be thrown out. if you pull rebound into the floor, and shoot over it (Gunite or Shotcrete) you create weak points. for consistency, all material should be BLOWN/SHOT into place.. If it was not BLOWN/SHOT there, it needs to be removed. YES, there IS more work to throw it out, clean it up, and haul it away. We are the only gunite company in our area, there are numerous Shotcrete companies here. Only a handful of them do the floors and wall CLOSE to proper. SO many people have cracked floors and/or walls due to pulling the WASTE/REBOUND into the floor. If you were not trained to nozzle/finish by someone that's been doing the work for 30 years, you most likely haven't learned everything you NEED to know. I myself have a LOT to learn, but REBOUND is BAD, THROW it OUT!

  With gunite, by the time the second truck arrives, i can usually walk on the first section of floor. When the Third truck arrives, i can shovel and jump up and down on the first section shot. I'm not sure how fast shocrete hardens, since I'm a Gunite Man.

• shotcrete is better by far gunite is okay but only as good as the crew I've been doing pools for 16 years seen it all tile guys like gunite because its a lot smoother surface and you ca scrape crap off very easy.but if its smooth then the marcite won't stick. gunite is like a sponge the pool wont hold water lay a hose on the top step the water wont even make it to the floor we shoot two pools every day and done a lot of repairs on gunite shells if gunite is so good then how come bridges and dams rant made from it gunite is no more then stucco mix sand and cement shotcrete has sand cement and stone, gunite has rebound lots of it if you don't stand over them and make them get rid of it they will bury it in floor i seen a guy drop his nail gun of the roof and it busted a hole in the gunite floor.you can backfill a shotcrete shell right away a gunite you have to let cure for some time they say 30 days with water sprayed on to get it to harden properly because they are shooting way to dry it stand up better but no better than beach sand till it gets some water i personally wouldn't have a gunite shell seen way to many problems.