Thoughts on Roof design for covered line

CYanchycki

CYanchycki

Club Coordinator
You will find attached photos of a roof design that my buddies home club is looking at errecting over there 14 bench firing line.

The concrete slab is 16'X86'. The plan is for the roof to be 15'X84' as in the picture.

The benches are back 4' from the front edge of the slab.

The thoughts are to have the roof edge start at 7' instead of 8' from the slab surface. The reasoning is to maybe aid in the ODD blowing rain storm. The benches are 6' on center. They are concrete tops with steel pipe feet I believe 6" in diameter.

There are a few concerns so I told my buddy I would ask the men who travel the US and shoot at various ranges.

1) What contributes more to seeing your rifle move point of aim when your neighbor shoots? Concussion from the rifle itself or the concussion bouncing off of the roof? So in other words ill the roof being a bit lower be a detriment?

or

is it how close your neighbor is to you?

or

if things are constructed properly you guys do not see that at ranges?

I am trying to help him out. This is a very SMALL club in North Eastern Ontario so money is not unlimited. They are trying to get it right the first time if there is a right. I did mention about possibly extending the front edge of the roof a bit but the concern is what effect will it have. I see to often at our home range when your neighbor fires your rifle shifts point of aim. You have to be very obsevent when your neighbor fires.

Thoughts gentlemen????????

Calvin







 
Roofs cause problems for sure

This is something I've thought a lot about. The ranges I shoot at have two pitch roofs with the steeper part toward the targets. This reflects your own muzzle blast right back at you, unless the front pitch is quite steep. It also causes up and down drafts if the wind is coming from behind. I put an "uppy-downy" wind flag in front of our benches, and it shows all kinds of unpleasant things happening. Ever have unexplained vertical? It may be your roof. Worst is a bench in the corner next to a berm under a roof like this. The "uppy-downy" goes nuts in every direction. There is a vortex there.

I would highly suggest a one-pitch roof with a shallow pitch and the high side toward the targets. This will give you the least wind and sound effects. Draw it out and see the reflection and wind angles for yourself. Better yet, make a model and do some smoke tests with an incense stick and a fan. If you must have a two pitch roof, put up a flat ceiling of some cheap, absorbent material.
 
roof desgn

I believe that a shed type roof would be best, an overhang on the front that is too long can be a problem , more then a help.
The nasty thing is roof materials. most use steel roofing that creates a lot of excess noise , due to muzzle blast.
a 5/12 or 6/12 should work well, . If you have the $$$$ use plywood and standard shingles.
Why plywood. { easy to repair} shingles easy to fix bullet holes {leaks}
Don't ask me why {bullet holes} I really don't know . I just know they will eventually be there''''
 
Calvin,
Has anyone checked the design for withstanding the design snow load? I am concerned that with no poles under the ridge and no truss structure, that it will collapse under a heavy snow. A local lumber yard that sells trusses should be able to help with a design for your climate.

Sound-absorbing material under the roof can help. Google "anechoic chamber" for some extreme examples. Finding something resistant to birds and squirrels may be a problem.

Cheers,
Keith
 
roof design

Your thoughts are correct as to snow load on that particular roof design. That style would be more to the likeing of a south west range and still be a bit marginal.
A truss design would certainly be a heck of a lot safer and practical. Ours are trusses, with steel deck type roofing materials. The reverb is quite loud to say the least.
Plywood is way quieter. if you wanted to you could also glue beadboard foam on the underside to help quiet , down the reverb.
The cost is marginal. Really hard to give a complete answer without your budget,
 
Direction??

What direction does the range face ? Looking into the morning or evening sun while shooting is very uncomfortable.
 
To answer a few questions

the roof design meets snow load requirements. The roofs in the picture are actual roadside picnic areas in NW Ontario. They get TONS of snow there.

In regards to direction they shoot, they shoot north. They had thought about plywood with shingles but there reasoning for going metal is the main firing line is in the shot fall zone on Trap nights. The main firing line is closed during those events. The thinking was it may stand up better to the falling shot than shingles.

The drawback, then damn bullet holes through the roof. The plus is the club is small, maybe 100 members so they have a pretty good handle on what goes on at the club in regards to vansalism. No fear of people walking in, to far to walk into the range from the main gate.

The few people I ahve talked to have felt that the proximity of benches to one another contributs more to your rifle moving than the roof.

Hope this aids a bit more.

Thanks in advance for your responses.

Calvin
 
A problem with steel roofs, as we found at Riverbend, is condensation. Especially in the fall and spring when the condensate freezes as frost on the bottom of the roof overnight, resulting in a rain the next morning. After putting up with it for years, we finally removed the roof panels, put down a layer of high density styrofoam board and reinstalled the metal. Problem gone.

The roof on our main range was originally shallow (1/12) simple single pitch to the rear but there was a problem with blowing rain. We added a steep pitch overhang to minimize that but there was then a noticeable increase in muzzle blast. As an educated guess for the least worse roof design, I'd suspect something like a simple single pitch overhanging the line by around 3 feet, maybe a touch more.

Our range faces north, I'd imagine that there can be significant air turbulence with a south wind. Ever seen a smoke enhanced wind tunnel picture of the airflow downstream of an aircraft wing with flaps extended?

PICT0624_zps8c2fe70b.jpg
 
TomD said:
... put down a layer of high density styrofoam board and reinstalled the metal.
Click to expand...

Seems like a good way to keep the styrofoam in place and not create nesting sites, too. How much did it help with noise?
 
mks said:
Seems like a good way to keep the styrofoam in place and not create nesting sites, too. How much did it help with noise?
Click to expand...

Noticeable but not dramatic. Another advantage is in hard summer days in direct sun. The metal roof heats up to somewhere around 130+ degrees and then, without insulation below, acts as a passive radiator, cooking anyone below. It is much cooler on the range now, it's still Georgia but much better.
 
Our Matches don't start till 9:00AM so I always wanted the roof to extend out far enough that it would block the sun in the morning, then have it extend in the back to keep the guys with the spotting scopes out of the rain. That way you wouldn't have to worry about rain coming in from front or back. Then have a staging area between, but behind the shooters, then the roof itself, metal with the foam or plywood to keep it from moisture build up, then hang chicken wire up and fill it with thick rolled insulation for sound deadening.

Joe Salt
 
I would suggest an overhang past the pipe columns of about 2'. This would help get the rain and snow to fall off the concrete slab and provide more shade. I like the shed roof if you are using steel for economy and simplicity. You might consider foam insulation on the underside for heat and sound. Would love to help you build this but I am in Texas.

Concho Bill
 
If you want a shed roof, steel becomes very attractive because of pitch limitations. Steel roofs are commonly installed at a 1:12 pitch where the lower limit for shingles is 3:12. Also you don't install plywood decking.

If you think it out, the entire framing process can become very simple and fast, no need for the standard 2' on center. That can be stretched out to whatever bay spacing you want/need if an appropriate beam is selected and then use dimensional lumber stood on edge as purlins @ 2'-0 OC to support the roof.

Sizes will vary due to bay depth, bay spacing and loading conditions. One thing for certain, it would be a devil of a lot cheaper that trusses.
 
Range Roofs

Calvin, attached is a picture of the shooting line at Caledonia Forest & Stream Club, one of the ranges referred to by vtmarmot above. All my photos are of shooters and none show a clear picture of our roof, but this one is close. As vtmarmot says, a roof of any kind increases reflected noise and the front portion of ours is angled to reflect muzzle blast right back at the bench. It's not unbearable with good ear protection, but it is noticeable.

The positive side, which to me overcomes the negative, is that it blocks sunshine in the shooters' faces, allows comfortable shooting in all but destructive conditions, and provides shade the heat and glare of the sun.

The metal roof does have minor condensation in the early morning of cold days, but is quickly dissipated as the sun rises. Not sure if a composite roof would do that or not. The metal sheds snow easily and we are content with it.

100_1974-web.jpg
 
Calvin,
As long as the cover you show is adequate for snow and wind loads adding insulation is simple and will help with sound attenuation and heat gain. Put up the frames, install the purlins (look like light gage lipped C-channels), screw chicken wire to the bottoms of the purlins, install batt insulation on the chicken wire (no facing is better for sound attenuation, but I don't know if birds will tear it up), and install the metal roofing. Batt insullation can be same thickness as purlin depth. I would suggest a 60 cm (for you metric types) roof overhang to keep rain and snow off the concrete pad.
 
metal roofs......

I've several and have these comments.

Corrugated metal with any sort of under-facing makes for great bat nests. They crawl up the channels during the day and come out at night. Or when scared by loud noises, if flying bats isn't a problem then ignore this part.

Corrugated metal WILL get running moisture on the bottom side. If you cover it with wood it'll rot over time. Typar membrane is designed to let the water run out the ends, still holds bats. IME open insulation will soon become a soggy mess, depending of course on climate. More pitch is better for drips.

Corrugated metal sheds snow like no other.

I make my roofs LARGE, overhang minimum of 22.5 degrees up and out from the muzzle to the eave, prefer 45 degrees of coverage. And I like to see the sky, which means 8-9ft (3M) minimum

I like metal roofs..... :)

I'll shut up now

al
 
The Purlins

That will be used are steel. 2x4x3/16 with 2' OC.

Thanks for all the ideas. I am relaying this info to the appropriate people.
 
It is interesting how different areas have different conditions that become important. Out here where I live snow is rarely a factor and neither is rain for that matter. Wind has to be a consideration and the sun is a huge factor. Where Al lives it rains a whole lot and bats will be a bother to you when you try to shoot. I would love to have a high pitched roof to shoot under but a light weight open 5 in 12 pitched metal roof, or greater, would be perfectly designed to fly in some of our winds.

We can utilize a very low sloped metal shed roof which is easy to build and probably the cheapest to build.

Concho Bill
 
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