At some point in the future, I am going to be building a “box” on the side of a house to store a generator in.
This box needs to house the generator even when in use.
A couple of questions…
What do you recommend for sound-proofing ? I know there is going to be -some- residual hum, no matter what you do, because the box is going to be built right on the side of the house. What suggestions do you have for ways to at least deaden the noise as much as possible ?
And secondly… Does anyone have any pics of good designs ?
Good looks, good security, good weatherproofing, etc…
Get over it……. The angry going eat you up. ~Brownbagg ’06
Replies
In the Army we used to dig them down into the ground. The dirst that was dug out would be used to fill sandbags which would be stacked around the hole. That kept 'em pretty quiet.
That wouldn't exactly work for you, since you want a roof over it. But you might be able to use a natural terrain feature to block some of the sound.
Or put it partway into the ground and build a shed on top of the ground around it.
I built a heavy rolling cabinet once for a big vacuum pump in an engineering office (for a large vacuum table). It had to have lots of airflow, but be quiet - I'll see if I can find pix.
Basically, I built a labyrinth of folded flat wide passages in and out of a 4'x4'x3' central volume. I lined everything with 2" thick sheets of the "egg-carton-like" black foam sheets from McMaster-Carr. I think the intake was a 4" x 48" along the base, and the exit was long the top
Worked darn well. - just a hum. Had internal temp sensors and a big outside display. Never overheated in there. It was actually quieter than the old office, where the pump was in an adjoining room.
Forrest
Can you make it a stand-alone but next to the house to maintain an air gap between the gen building & house? That'll isolate sound transmission.
not only that, it willbe a safer thing re fire and CO protection.Luka - be sure to extend your exhaust stack way above the house so you don't kill yourselff with CO gas
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Some things to remember: The enclosure will need provisions to allow combustion air to get in as well as cooling air in and out, enough room to access the generator for maintenance, a way to route the exhaust pipe out through some sort of thimble to keep the hot pipe away from combustible materials, fire wall protection for the house, plus you need to make sure there's no way for exhaust fumes to get in the house. I assume this is a small generator, maybe 3kw or 5kw, something like that. If it were me, I'd locate it away from the house in a little doghouse-like structure.
air cooled or water cooled?
Most noise from my Onan air cooled is from the muffler. I would be looking into some aftermarket better mufflers than the lawn mower style if I were running it more than occasionally.
Time you add a stack, and a better muffler, you might end up with more back pressure that would make it harder to start, so You might want to add inline a bypass fitting for startups.
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I have always thought if I built a generator shed (building), that I would construct it out of CMU for sound deadening. But I've never had a chance to try it yet. I would also increase the base isolation (accoustic isolation mats) under the generator. And for venting (both air supply and exhaust), a couple of 90 degree turns through insulated ducts will reduce the transmission of sound somewhat. Ditto on the improved muffler recommendation.
because the generator would need to come on during a storm, I would build a bomb proof shelter maybe like somebody said. CMU, I would fill with concrete and rebar. Maybe a concrete slab as a roof. A hurricane proof bldg.
What size generator?
ICFs, hinged shed roof of a ply/foam/ply sandwich lock on the roof...
My uncle has a shed where he has run the wiring, has an exhaust door for the generator on wheels to roll to when in use.
what size generator.. what motor???
you may be able to add a baffle exhaust or just a simple extension..
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WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
This is not at my house. If it were mine, I wouldn't care about how it looks, or several other concerns.
Youse bring up some good concerns.
~~~
It's a 5000w generator.
I don't know the HP.
I do not believe extending the exhaust is an option.
Ease of construction puts it up against the house, but other concerns have moved it, in my mind, away from the house.
The central location it has been sitting will also be changed, so that the exhaust fumes will be forced away from the house.
I was already thinking 4 to 6, 4" holes in the sides, for ventilation. (2 or 3 holes per side.) Now I am thinking that I may include a trap door near the bottom, right next to the exhaust, that can be opened for extra ventilation while it is running.
(Of course, this means more noise again. So I need to figure out a way to have really good ventilation, but dampen as much noise as possible.)
With our weather, rainproofing is a must.
I intended to construct it so that the entire top raises. Also, the entire front will fold out, or be otherwise removeable. Both, for ease of getting to the generator, and/or getting the generator out, if it needs to be worked on.
It has been quite a long time since I built something and was concerned about esthetics. I am positive I have lost my touch.
But I am concerned about esthetics now, and I was hoping some here would have some good pics of examples of well built, and good looking enclosures they have seen, or have made, themselves.
It doesn't matter if it was made for a generator or not, as long as it looks good, and the idea can be adapted.
~~~
Something I am considering...
Start with concrete block walls. Bricks may be even better, I can leave gaps with bricks easier than with blocks. Although, on second thought, a block laid sideways, here and there....
Strong. Use these for the back and side walls, up to a point, then build up from there.
Also keeps combustible materials farther away from the hottest points on the generator.
Set the generator on a pallet. Anyone have a better idea for that ? Setting it on the concrete will transmit the vibrations directly to the slab.
~~~
So..... Anyone have any good pics ?
Get over it....... The angry going eat you up. ~Brownbagg '06
How quiet?
How much room to work with?
What's the dollar and labor budgets?
You can go with soil filled tires for a wall, RR ties and more dirt for the lid. Quite effective, lo dollar, hi labor.
Double masonry walls with sound batts between. Isolated floor and inner walls and baffled ventilation like McDesign described. Very effective, hi dollar, medium labor compared to material.
Something in between?
2x4 walls, well caulked fiber cement siding. R19 FG insulation overstuffed in the bays. Add 1x2 mooney wall. Over this, add verticle 1x2s spaced between studs. To this attach a double decker sandwich of 30# felt and hi-fiber mastic applied with 1/4" notch trowel. Then Zbar in betweeb Mooney layout and 1/2" DW, finally, Verticle Z bar on stud layout and 5/8" type X DW. Seal all airgaps on each layer.
Carry the same airtight multi-layer, multi-density, multi-rigidness thing across the ceiling.
Suspended floor on slab foundation. No part of the suspended floor should touch the walls. 2x6 floor joists on 2x8 rim joists leaves 2" clear below, lay 3 layers (1 1/2") foam carpet padding from wall to wall, even under the rim joists. Leave the floor framing 1" shy of the walls and the sheathing 1/4" shy. Some industrial vinyl base moulding to cover the gap.
SamT
Now if I could just remember that I am a businessman with a hammer and not a craftsman with a business....."anonymous". . .segundo
How quiet ? How much money ?Well, my guess is probably some compromize between the two.It doesn't have to be a fortress of solitude. I am strongly leaning toward CMU for the back and side walls. Then 2x4 construction for the rest. I think Grace ice and water sheild will do better than your idea of sandwiched 30# felt and mastic, with a lot less trouble. I was already thinking of using the grace for both it's sealing and it's soundproofing qualities.A pallet on the floor, which, as you said, doesn't touch the walls. I may make the "pallet" myself, for a custom fit. With a rubber mat on top of that. I can figure the whole thing out as I go. I just like to get ideas here. I forget the measurements of the generator, but I want at least 6 inches of clearance all around.Already have ideas about setting short pieces of electrical conduit in holes in the concrete blocks. Mortar/cement/epoxy those in. Then use allthread through those to make the hinges for the front and the top.
Get over it....... The angry going eat you up. ~Brownbagg '06
I've got a generator in a shed about 75' from the house, sits on a pallet, one osb wall between us and it...I have to run it for a week every 5 years...if it's too loud, I turn up the tee vee<G> Oh God said to Abraham, "Kill me a son"
Abe says, "Man, you must be puttin' me on"
God say, "No." Abe say, "What?"
God say, "You can do what you want Abe, but
The next time you see me comin' you better run"
Well Abe says, "Where do you want this killin' done?"
God says, "Out on Highway 61."
Why do you have to run the generator once for a week evry five years ?
Tim
Why do you have to run the generator once for a week evry five years ? Mother Nature<G> Oh God said to Abraham, "Kill me a son"
Abe says, "Man, you must be puttin' me on"
God say, "No." Abe say, "What?"
God say, "You can do what you want Abe, but
The next time you see me comin' you better run"
Well Abe says, "Where do you want this killin' done?"
God says, "Out on Highway 61."
Now THAT'S a strong bladder !!!!!
Get over it....... The angry going eat you up. ~Brownbagg '06
Why do you have to run the generator once for a week evry five years ?
Mother Nature<G>
Im not askin you NOTHIN else! Not till tomorrow maybe . <G>
Tim
Some years ago, Tauton's Code Check website used to show how to add a ground wire to an existing two wire circuit. It was basically just add the ground wire and take it back to a legitimate ground. I have looked for that section and can no longer find it on-line. I also have their new edition of the Code Check book and it is not in there.What I did when I needed a ground for my computer was to carefully drill a hole from the receptical down through the floor and feed a bare ground wire into the crawl space and over to a ground rod. I am now in the process of modifying some of the wiring, so will tie the ground wire into the equipment grounding conductor bus in the main panel. For most purposes, a GFCI without a ground wire should suffice to allow the use of a three prong plug and have shock protection. For a few applications, such as for a surge protector, a wire going back to a known ground is still the best option. The added ground wire should be at least as large as the current carrying conductors.
ok?????
ROFLMBOI think he grounded out his keyboard.;o)
Get over it....... The angry going eat you up. ~Brownbagg '06
Years ago I took a brand new McColough generater down to the deer camp. We put it as far out in the woods as our cords allowed. We were sitting around the fire drinking but we could hear the noise.
One of our members owned an upholstery shop and brought a load of foam cushions from old sofas so we could use them to start the campfire.
My wife's young brother decided he could use these to quieten the noise which he tried without telling anyone.
Shortly after he came back the lights began to dim and went out but we could see real good because about ten cushions and my generator were lighting up the whole area but it was really quiet.
priceless
My thinking goes to less elaborate. Instead of trying to totally enclose with five walls and contain all the moise which you can't do well because it still needs holes to breathe - to jsut build a basic enclosure against weather, and then build a single CMU wall between it and the house to reflect thenoise the other way. My last installation was a water cooled deisel genset in a metal bow made for exterior setup. We placed it on the opposite side from a free standing garage. You hear it fine on that opposite side, but nobody in the house can hear it running. The garage just bounces the sound waves in the opposite direction. In another one we did tenyears ago dimilarly, I guess it works fine too. Last summer we had an outage and the owner called the electrician to ask him to come see why suddenly some of his lights were not working.Sparky simply asks, "Do you know most of the island has no power at all? Your generator is probaly running and supplying the select emergency circuits". The HO was totally unaware of the generator running 'till he had walked out to the garage to check.again, like I say, most of the noise comes from the exhaust and yuou have to vent that out wnyway, so a super tight enclosure does little good when the main noisemaker is a pipe sticking out of the structure, so bounce that noise off a wall telling it to go thataway.'course, if this is in a tight lot with near neighbors, that creates another problem...;)
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It's in the city. A close lot, with neighbors that are bothered by the noise.The noise is an issue for two reasons. Bothering the neighbors, and "advertising" the fact that you have a generator, to would-be thieves. My thoughts at this time...CMU block walls on the back, and the two sides. Aim the open "front" away from the house.Bottom row of blocks on the back wall, laid on their sides. The rest of that wall put up normally. The sides put up normally, with some blocks on their sides near the top.The front wall will be built from PT. It will be a lift out design, and will inlcude a fan with louvres. That fan will be on as long as the genset is on. It will pull the fumes out of the enclosure, and pull cooling air in.The top will be PT as well. Possibly decked, and covered with a nice green metal roofing.Another "back" wall made of the cmu blocks, will go two to three blocks high, and will wrap the sides for about a block or two. This will be 8 to 10 inches away from the structure wall. This will allow plenty of air to enter the structure, yet turn that noise sideways and up.Possibly look at some sort of sound mediating treatment for that second wall, as well.The genset will sit on a PT platform which itself will sit on a rubber mat. Then another rubber mat on top of the platform, and under the genset.I'm thinking that if I fill the cavities in the blocks with cement, I will not only have anchoring for bolts here and there, but the extra mass will help muffle the sound.Now I have to start trying to figure out what the budget will be for all this...
Get over it....... The angry going eat you up. ~Brownbagg '06
If you go the CMU route and want some additional sound deadening without having to fill them with concrete, fill the cores with sand - sand is an excellent sound absorbing and deadening material.For the roof insulation, you can get special fiberglass accoustical panels. However, it might be easier to just get the sound deadening duct board. If you wanted to get more elaborate, you could also fashion an air inlet baffle out of the insulated air duct material. A couple of right angles in the air inlet duct and it should attenuate the sound emitted while still allowing ample air.
Website: http://www.naima.org/pages/products/ah.html
There are a lot of other sites dealing with sound attenuating ducting.Celotex also makes a good sound attenuating panel that I have used behind wall board. It works much better than regular fiberglass insulation for sound attenuation, but I don't know how it stacks up against the special fiberglass that is engineered for sound attenuation. Unfortunately, Celotex does not fare too well if it gets wet... There is another fairly well known manufacturer of similar stuff, but my CRS has kicked in...Be sure to screen the openings to keep the little critters out - mashed mouse doesn't smell so good after a couple of days...If you are worried about theft, you may want to place the generator on a concrete base with some strategically placed anchor bolts to secure the generator. If they are sufficiently paranoid, you might even want to epoxy the nuts to the anchor bolts. Someone could, of course, still get it but it would probably deter all but the most determined and well equipped. My experience with the plastic "egg crate" foam material is that it disintigrates after a few years. A decade ago, I used some to line the cases that I use to haul my pro-photo strobe lights around. Several years ago I opened the cases after a couple of years in storage to find that the foam material had disintegrated into a sticky granular mess that was a real pain to clean up.
I may have missed something here, but why not buy a larger whole house generator in a lockable all-weather cabinet, whose price increase would be offset by not having to build the enclosure? I bought a Kohler 12RES 12k generator and bolted it to a concrete base. From a few feet away, you can barely hear it running.
A few thoughts.
A few years ago DW and I invested in a motor home generator . They set on rubber bushings that act as springs and it has a well designed muffler . So well designed a muffler it hums . It is only a 4,000 Onan but its cost was 1895.00. I can buy the same size generator from Sams right now for 350.00 but not quality.
You get things like constant run and quietness out of an expensive generator. They will run a long time constant run.
The first one I bought was for a comapny I worked for and he was looking for somthing quiet . We took one from a house boat and mounted it for transport for job site use. It was very quiet and thats how I learned the difference . You could hear measurements being called out close to it as it was very quiet .
If you think about motor homes that have a unit under your bed , it tells you that the technology is already there for a cost.
I was thinking about firing a cabin with such a generator but I had several questions you might think about as well.
I needed to lock it up so no one could steal it or a child couldnt tamper with it . It was to be a rental cabin so I wanted a switch inside to turn it on when they needed it and turn it off at night when they went to sleep and thus run off batteries just like a motor home . It had to have an idle for times when there was no power load .
I know any gas motor puts out heat and needs to be kept cool . It also needs combustion air as will as exuast. Shade is a big deal as well along with being kept dry. Ideal would be an updraft of fresh air to keep it cool but how bout the moisture?
How bout locking it up so no one could possibly steal it with so much air to it ?
Then your concerns about quiet with so much air to it ?
Anyway theres a cabin in the mountains a couple guys put in a metal lock box thats supposed to be like a utilities lock box with a lock that cant be accessed in a 3 inch pipe. I havent seen it yet but the need passed at least for now . Id still have conserns about the other things using a utility lock box.
Tim
Why re-invent the wheel? Most generators have optional sound control packages, that you can get in place of the "standard" muffler. these work quite well. Otherwise, something as simple as a screen of hedges can make a big difference. There are two basic approaches to sound control: absorption and reflection. Most of the ideas presented so far suggest ways to absorb sound. In the simplest manner, reflection can be used to send sound where it doesn't matter ... say, straight up. Placing the generator in a concrete "bowl" would be a start. Likewise, concrete or block walls can greatly reduce the sound sent in a particular direction. In a more clever application, reflections can be made in a manner where they cancel each other out. This principle is use in both muffler and tire design. But, as I said ... why re-invent the wheel? I'd start with the genny manufacturer, and see what he suggests.
I think I would build a little shed, and put a small automotive muffler on the generator. Since your finances are known to be limited, I would look for a good but free takeoff at a muffler place. Put threaded pipe on the generator with an adaptor of some sort to go to flex pipe to the muffler. If you dont use flex, there is a risk of damage to the engine from mechanical stress. Flathead engines are noiser than ohv, so it may still be noisy, but will be a lot quieter. If you have ohv, you're way ahead.
I have a small 5hp very old generator that works well, but is noisy. Fortunately power outages here rarely last more than an hour or two, but if we get ice storms, can be a lot longer. The real problem is having enough gasoline on hand. I think the answer to that is to have a bank of batteries charged up with an invertor to prove lighting and light duty AC. Then you can run the generator in shifts to recharge the batteries and provide the heavier loads, like refrig etc. If you could rig a propane carb to the generator, that would be handy. Plans are on the internet, and I believe they may be commercially available. Maybe one from a RV generator would work.
OK, one thing you have to get over is that no one is going to be living inside the walls you are making here. You can think outside the box a little... about this box you are building.
My thought is this: Use Hardypanel, 4'x8'x5/16" cement board - very dense and fireproof. Ment for the outdoors. Make an outer box that people will see. Make a smaller inner box that houses the generator, mounts, air intake, exhaust, and fuel feed. In the gap between the two boxes, fill with sand. No sound is going to transmit through an inch or two of sand. Make a couple of stacks baffled with the cement board and surrounded by a double walled sand shrouded tube.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Use several layers of drywall or cement board for fireproofing. Will also help with the noise. Should go up and to the sides several feet beyond the walls/roof of the enclosure.
Be sure to check local codes before starting. What you propose is likely illegal (absent extraordinary precautions) in many areas.
Building a doghouse sized concrete block box for a generator is illegal ???Wow you have some hefty building restrictions where you live.=0)
Get over it....... The angry going eat you up. ~Brownbagg '06
Building an attached structure for a generator may be a code violation unless extraoridinary measures are taken to protect from fire and CO hazards. Similar to the situation for a transformer in many cases.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
Ah.Ok, I see.This is not going to be attached. That was the plan at first, but not anymore.Around here, whatever you call it would have to be 6 feet from the house. And there are other setbacks. But that's about it.You could build a 200 sq ft "shed" to put it in, without a permit...=0)
Get over it....... The angry going eat you up. ~Brownbagg '06
You mentioned a shed - That got me to thinking.I wonder if the place could USE a new shed Like maybe a 10X12 shed with the generator in the back?Most people can use extra storage. And you're definitely skilled at building 10X12 sheds, if I recall correctly.(-:
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