Trap rock size for "pad"?

[Turfmaster6]

Hello,

I'm putting in a "pad" around my shed I've removed 3-4" of top soil and about to put in a layer of trap rock topped with stone dust. My guy has 3/8" and 3/4" trap rock possibly one size larger too. Can anyone enlighten me as to the considerations in selecting a size?

Mike

 

[dave1949]

I had to look up trap rock. Obviously don't know anything about its use.

What is the pad going to be used for? Will you drive vehicles on it? Just covering up the ground with something to keep grass and such from starting? Splash zone for the roof run-off?

 

[stuckmotor]

My neighbor's contractor used a similar base for his driveway. As I remember, it was cruhed granite topped with sand. I guess this was done to keep the granite from cracking. Could someone tell me whether I've guessed correctly and why it's superior to the earth that's always been there?

 

[JD 4520]

Hello,

I'm putting in a "pad" around my shed I've removed 3-4" of top soil and about to put in a layer of trap rock topped with stone dust. My guy has 3/8" and 3/4" trap rock possibly one size larger too. Can anyone enlighten me as to the considerations in selecting a size?

Mike

Size is generally based on the base ground. The harder the ground, the thinner the layer of rock and smaller (3/8") rock can be used. The softer the base then you need to build up using larger rock on the bottom and gradually smaller over top. The smaller rock allows simply for a nicer smoother road (or pad in your case).

For instance, where I live, the ground can be softer due to the wetness. I built a road to my house using 4" base, then 1-1/4 to 2" cover followed by 1/2" on top of that. I have a very firn but smooth road. The trap rock locks into the base ground and to itself and so on. You generally don't want to or need to put larger rock on top of smaller rock as it doesn't serve a purpose if that makes sense.

Good luck.

 

[Turfmaster6]

Size is generally based on the base ground. The harder the ground, the thinner the layer of rock and smaller (3/8") rock can be used. The softer the base then you need to build up using larger rock on the bottom and gradually smaller over top. The smaller rock allows simply for a nicer smoother road (or pad in your case).

For instance, where I live, the ground can be softer due to the wetness. I built a road to my house using 4" base, then 1-1/4 to 2" cover followed by 1/2" on top of that. I have a very firn but smooth road. The trap rock locks into the base ground and to itself and so on. You generally don't want to or need to put larger rock on top of smaller rock as it doesn't serve a purpose if that makes sense.

Good luck.

Fantastic explanation and helpful example.. thank you very much! My GC2310 is the only vehicle that will be on this, and a couple of motorcycle trailers will be parked on it. It's mostly silt the base will be sitting on pretty good drainage over in that part of the yard Maybe I'll go with that largest size for my base. Does the stone dust sound like a good idea for the top layer or go with the small size trap rock? I intend to rent a vibrating compactor to tamp everything down.. make sense? If so, would I do that between layers or after all the stone is down?

Many thanks!

To the other gentleman that I don't know what I'm doing. TEN RING You couldn't be more right! LOL

 

[vtsnowedin]

The point of replacing topsoil with crushed stone is that the stone doesn't turn to mud when it gets rained on. This gives you a surface that you can drive on without it getting rutted in all weather. The stone dust on top chinks the coarser stone together so you don't have that driving on marbles effect where the tires ding stones off to the side. If your just putting a drip edge down the sides of your shed you don't need to chink it but you might want to put a geotextile under it to keep weeds from growing up through. Shape the subgrade so that it drains away from the shed and outlets in the direction that keeps the water out of the drive and away from your other buildings.

 

[dave1949]

Fantastic explanation and helpful example.. thank you very much! My GC2310 is the only vehicle that will be on this, and a couple of motorcycle trailers will be parked on it. It's mostly silt the base will be sitting on pretty good drainage over in that part of the yard Maybe I'll go with that largest size for my base. Does the stone dust sound like a good idea for the top layer or go with the small size trap rock? I intend to rent a vibrating compactor to tamp everything down.. make sense? If so, would I do that between layers or after all the stone is down?

Many thanks!

To the other gentleman that I don't know what I'm doing. TEN RING You couldn't be more right! LOL

Poor sentence on my part, I looked it up and I don't know anything about its use, is what was meant.

 

[JD 4520]

Fantastic explanation and helpful example.. thank you very much! My GC2310 is the only vehicle that will be on this, and a couple of motorcycle trailers will be parked on it. It's mostly silt the base will be sitting on pretty good drainage over in that part of the yard Maybe I'll go with that largest size for my base. Does the stone dust sound like a good idea for the top layer or go with the small size trap rock? I intend to rent a vibrating compactor to tamp everything down.. make sense? If so, would I do that between layers or after all the stone is

Direct answer is I suggest using small rock. Smaller rock that what is below will inter lock and create a strong stable base. I wouldn't see the need to add anything more on top of that but say you we're building a road and you desired a real nice smooth surface, you might add stone dust.

Crushed rock on a driving surface is consider impervious surface. That means it drains like a concrete driveway - in other words it doesn't.

 

[Turfmaster6]

Poor sentence on my part, I looked it up and I don't know anything about its use, is what was meant.

Dave.. no worries… you'd have been very correct with the unintended interpretation too! Zero offense taken

Mike

 

[Turfmaster6]

Thank you all for the excellent replies I still need to fill in the trap rock at the far end and behind the shed. From the replies above, it sounds as though there are two or even three choices.

1. Stone dust
2. Small gravel (or smaller trap rock)
3. More big trap rock.

I've learned much from what you've said so far what are your thoughts on one vs another of these above? Sounds like the stone dust does NOT drain (is this "crushed rock"?) As I intend to add a "portico" type overhang behind the shed, I won't be adding the top layer there I can pull the trap rock back cleanly when the ground unfreezes, dig the holes for the columns and then finish it up right.

Also anyone got any tips for protecting your driveway from loads of material being dropped off? Took HOURS to clean it off after the first round!

How things look so far 10 of the 16 yards of trap rock down so far. Final grading not done yet.