Dust Collection System on Garage Roof

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Forum topic by cayvman posted 10-19-2019 05:01 PM 551 views 0 times favorited 20 replies Add to Favorites Watch
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7 posts in 1568 days

10-19-2019 05:01 PM

Topic tags/keywords: dust collector dust collection garage roof top

Looking for any comments, suggestions or cautions regarding my plan to relocate my dust collection system on the roof on my garage.
Particulars: My workshop is located in the garage, it’s small taking up one half of a two car garage (about 10×17). Because of the size of my shop, all tools are on mobile bases (DC, table saw, band saw, planer, jointer, drill press and bench). Only bring in the planer and drill press when needed. Located in Southern California.

My plan is to build a shed for the motor, cyclone and chip collector bin. Then run 5 inch pipe along the roof with two possibly three drops into the shop below. I will use flat roof pipe flashing for the drops into the shop then install blast gates at each drop. Thoughts on how best to run the drops into the shop below…

My garage is not heated or cooled, so loss of conditioned air isn’t an issue. Make-up air is, though.
Thoughts on this or anything I haven’t addressed is appreciated.

20 replies so far

View Fred Hargis's profile

Fred Hargis

5799 posts in 3029 days

#1 posted 10-19-2019 08:16 PM

How will you keep track of the dust level in the bin? Other than that there isn’t any operational problems with the plan. I suspect someone will counsel on the roof penetrations.

-- Our village hasn't lost it's idiot, he was elected to congress.

View cayvman's profile


7 posts in 1568 days

#2 posted 10-19-2019 10:42 PM

Will either manually go up and check it, have built a stairway for access or I will add an Arlo camera to my existing system and check it that way.

View ibewjon's profile


1035 posts in 3328 days

#3 posted 10-20-2019 01:00 AM

I would penetrate the roof once, then run duct about 3’ high, horizontally along the wall. My DC is in a corner, with duct run 3’ high. I put in the y fittings,5” run with 4” tap for each tool. As little flex as possible. I would keep the roof penetrations to a minimum.

View fivecodys's profile (online now)


1518 posts in 2171 days

#4 posted 10-21-2019 08:25 PM

This is an interesting idea but it seems like any issues you have with the DC will require a trip up onto the roof.
Dragging a full bin of sawdust down off the roof does not seem like much fun to me.
I also agree with the previous poster that multiple penetrations in the roof would not be wise.

Have you thought about building a lean-to on the outside of the shop instead?
You could also mount the blower and the cyclone up high in one corner of the garage. That’s what I did.
It cut the floor space used by the original configuration in half.

I really like thinking outside of the box but the roof idea might cause more problems than it solves.
Just my 2 cents.

-- When you leave your shop for the night, make sure you can always count to 10.

View Madmark2's profile


538 posts in 1124 days

#5 posted 10-21-2019 10:48 PM

You are increasing the static load on the system as your blast gates will be at the tool and not at a manifold on the roof. The whole system needs to be vacuumed down before the first chip flies. Additionally a 12’ or so lift from the floor to the DC will require a HUGE DC, how big is yours?


View cayvman's profile


7 posts in 1568 days

#6 posted 10-22-2019 01:46 AM

This is the type of feedback I was hoping for. However, my blast gates will be at the ceiling of the workshop. Does that make a difference? As my workshop is so small, I don’t have dedicated locations for my equipment, except when they’re idle. Hence having the blast gates in the ceiling.
Why does the system need to be vacuumed before “the first chip flies”?
My DC is not huge 1 1/2 HP. A modified Jet System with a Cyclone.
How huge would I need it to be for a 12’ +or – lift?

View ArtMann's profile


1441 posts in 1351 days

#7 posted 10-22-2019 01:57 AM

I do not agree that the location of the gates has an effect on the performance of the system. The vacuum in the system will equalize in the time it takes to spin up the fan.

View Madmark2's profile


538 posts in 1124 days

#8 posted 10-22-2019 02:12 AM

The more piping there is, even if capped (blast gate closed) the air inside that run has to be removed before the suck can reach the open end. Since few dust systems are perfectly air tight extra plumbing means extra (albeit small) leaks and thus more of your vac is going to pulling the inside of the hoses than coming out the end. This is called static load. Close everything and measure the vacuum in different configurations and you can measure for yourself.

Water pumps are rated by their lift capability. Same with DC’s. The more lift, the more power needed. A low and level DC run will be best vs a series of roller coasters. Don’t get me started on how bad hose reels are for dust collection!


View Woodmaster1's profile


1264 posts in 3122 days

#9 posted 10-22-2019 03:26 AM

The school where I taught added on a new building and they moved the dust collector from just outside the shop wall to the roof. I went from great dust collection to terrible dust collection it just did not have the same vacuum. You also need to replace the air being sucked out. If you air condition or heat a shop not circulating the air back to the shop you will lose the conditioned air which will increase your energy cost.

View therealSteveN's profile


4079 posts in 1109 days

#10 posted 10-22-2019 04:29 AM

The largest woodworking plant/company/single building I know has their DC on the roof, and they dump the sawdust into an enclosed truck box on a 2 1/2 ton truck, so no dumping dust, but they make a lot of trips to empty the truck.

That said it is LOUD. My shop is behind our house, the neighbors behind me are closer than my house. The only complaint I have ever had was the noise from the DC, and mine is indoors, and I only have a 2HP unit. Only adding that because the sound of mine out, and up in the air would be to those neighbors like an air raid siren. Enclosed it would really need to be tight I would think. Too tight then you may need some air into it? Agree the dust needs to come down to the ground, would be much simpler if you piped it down, rather than tried to carry, or drag it down.

-- Think safe, be safe

View clagwell's profile


42 posts in 328 days

#11 posted 10-22-2019 09:24 AM

You are increasing the static load on the system as your blast gates will be at the tool and not at a manifold on the roof. The whole system needs to be vacuumed down before the first chip flies. Additionally a 12 or so lift from the floor to the DC will require a HUGE DC, how big is yours?


- Madmark2

Well, yes, there is additional static pressure drop in that situation but I don’t think it’s enough to be really concerned about. For a 12’ lift the additional pressure needed is about 0.18”w.g. Even a small DC will have a total pressure of at least 7” so the 0.18” causes roughly a 1% drop in CFM.

-- Dave, Tippecanoe County, IN

View pottz's profile


6639 posts in 1520 days

#12 posted 10-22-2019 02:36 PM

id reconsider that your talking about the noise as said plus your gonna need a lot of cfm and then the trouble of cleaning and emptying the drum,i know it sounds good to save space but it sounds like a big pita to me.

-- sawdust the bigger the pile the bigger my smile-larry,so cal.

View cayvman's profile


7 posts in 1568 days

#13 posted 10-22-2019 04:48 PM

I did a db analysis using an iPhone app and the noise at the unfiltered outlet was 85db. Assuming a noise reducing filter would bring this down somewhat.
Will demo the cfm by putting the DC on the garage stairway landing and using flex hose. Will see the drawing power or lack thereof.
Just to clarify my current system, using an Oneida Super Dust Deputy.
Regarding the drops, reconsidering only doing one drop to the center of my workshop, being that it’s only 17’ deep and all my power tools are on mobile units. Using flex tubes to connect to tool.
The pain in emptying the 25 gallon bin is worth having the additional space when you consider my shop is a whopping 170 sf.

View MrRon's profile


5767 posts in 3779 days

#14 posted 10-22-2019 08:54 PM

You haven’t mentioned how you would protect the DC on the roof from the elements. Will it be enclosed? or left open?

View Aj2's profile


2529 posts in 2333 days

#15 posted 10-22-2019 09:14 PM

He also doesn’t mention the type of roof.
. Flat with hot tar or torch on. Or sloped roof with shingles.
I can say for sure most Residential roofs down fare well with foot traffic. Even a weekend of walking on them can take its toll on the top.
I have my cyclone outside of my shop in a shed roof. I have a 3hp tempest.

Good Luck

-- Aj

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