People Continue to Shovel Their Roofs , Truss Builders Say No Need To

Saturday, January 17, 2009 08:13 AM

Three men shovel snow off a home in the city although a truss designer says it really isn't necessary

Prince George, B.C. - Residents in the city continue to shovel their roofs. This comes after Royden Carey a truss designer with Winton Global homes (which designs and builds trusses for all over Canada and the USA) said there is not enough snow on your roof in the city to shovel it.

Carey says that the present snow load of about ¾ of a meter has measured out to be about the equivalent of 17.5 lbs per square foot on your roof. Even old trusses are designed to carry a load on your roof of about 50Lbs indicating that there is plenty of room left for a snow load.

( at right, a small greenhouse shows no sign of buckling under the weight of the snow on its roof)

Comments earlier that you should shovel your roof were met with statements from a number of high profile building contractors that you will run the risk of doing more damage to your roof than good by going onto to it to shovel snow.

Contractors say the snow we have received this year so far is light but beyond that we have not had any where near the load that would cause damage to your roof and shovelling just a portion of your roof will run the risk of doing damage by creating an uneven load on the trusses which could create a problem.

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Posted on Saturday, January 17, 2009 08:13 AM in News by 250 News

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Comments

Posted by: scruffy on January 17 2009 9:02 AM

will they pay the bill ,when it's on my kitchen floor,or my roof leaks and i have water stains on my sealing....not!!

Posted by: red2b on January 17 2009 9:12 AM

who will pay any of your bills when you fall and break your leg (or neck) while you shovel the snow off of your roof (for no reason). After all, what would a truss designer really know?

Posted by: Andyfreeze on January 17 2009 9:31 AM

I really don't understand why this is even an issue?
If you want to shovel your roof,then shovel it!
Who cares?
I had a LOT of snow on mine, and it is shoveled down to a depth of about 6 inches above the shingles.
I would rather do it now when the weather is half decent than wait until it snows like hell again and have to get it off in a hurry!

Posted by: Lamb on January 17 2009 9:32 AM

I don't know what it takes for you to understand that you do not need to shovel your roofs. Engineers, Architects, the truss designer (I would guess) all would measure the psi of the load on the roofs and are saying no need to do it.
The City has done a great disservice to the people to dessiminate fear amongst the population.
Snow is also a good insulator (save on your gas bill).

Posted by: Outwest on January 17 2009 9:50 AM

Tin Roof works great no need to shovel ,one drawback you do have to watch for the Snow sliding off, have a safe day clearing your Roof if you must.

Posted by: gus on January 17 2009 10:32 AM

It is one thing to shovel snow from the roof when you wish to. It is your house. It is another when the CHIEF CITY BUILDING INSPECTOR is quoted as saying that it needs to be shovelled, that it is wetter than normal snow, that new houses are MUCH stronger than those build before 2004 or something like that, etc.

Whether the Citizen got it wrong in the interview or whether the inspector got it wrong, it is the diligent thing for both parties to stop considering only themselves and start considering the people of this City who are being duped, spending money to get it cleared or putting themselves and their roofs in danger.

Anyone can dig up their yard to replace the sewer pipe from the house to the City connection. However, when the CHIEF BUILDING INSPECTOR says that after 20 years that pipe might be broken, might separate at joints, might be leeching sewage into the soil, etc. and is essentially doing nothing differnt from yelling FIRE for no need in a crowded room, then the City needs to do something to correct the error.

Posted by: gamblor on January 17 2009 11:33 AM

the chief city building inspector is a moron.

Posted by: red2b on January 17 2009 11:34 AM

Well said Gus.
Are you suggesting that we should dig up our front yard to check the sewer connection? Dammit, I just put all of the snow from my roof over that area!

Posted by: MrPG on January 17 2009 12:26 PM

As others have said, shoveling your roof is completely unnecessary under the current conditions. The Citizen should have done their homework before printing that story.

Thankfully, we haven't heard (yet) of a major injury because someone fell off their roof doing something they don't need to do.

Posted by: Fuzzy on January 17 2009 12:34 PM

You talk and talk and hope they'll listen, but no.... What's a mother to do?

Posted by: gus on January 17 2009 1:27 PM

red2b ... ROFLMNAO

Posted by: heidi1555 on January 17 2009 5:42 PM

My attitude also is who cares Andyfreeze. Shovel if you want, leave it if you want.
I say if you are going to stress to the point of b$%&*ing about it to your wife everyday or sitting straight up in your bed in the middle of the night because a kid accidentally kicks the wall in their sleep and you think it's your carport caving in then get up there and shovel it!
Needless to say he still hasn't gone up there and shoveled yet! I guess he's learning to chill.

:)

Posted by: northman on January 17 2009 7:29 PM

I say risk manage it because not every home and structures are the same. If it buys you peice of mind then shovel your roof but leave the 6 inches or so for insulation and shingle protection. Some common sense also tells me that multiple heavy snow loads over the years cant be all that great for structural integrity as well. When you cant close doors in your home because of the weight on the roof (some friends of mine have had this happen in fort st james) you should proably shovel the roof!! Ive also witnessed the aftermath of a sawmill collapse because the roof wasnt shoveld off.. Years of snow load and stressing resulted in weakning of the beams and girders. I may not be an engineer but from what ive seen snow do shoveling the roof buys alot of peice of mind! Cheers!

Posted by: gus on January 17 2009 8:06 PM

It is interesting to observe what the average person thinks about matters that deal with applied science and engineering.

Material fatigue is not something that is a factor in platfrom frame house construction. It can be a factor in more non-standard types of building designs. It is generally taken care of by by engineers when they use Limit State Design calculations. It is especially applicable for composite wood materials.

The jamming of doors in truss roof buildings in northern climates is a problem associated with something called "truss uplift". In a standard Canadian built home, the bottom chord and the top chords of wood trusses are in two separate environments. The bottom chord is typically insulated while the top chords are not and go through both a temperature and moisture change while the bottom one does not.

A truss is a closed, triangulated system. With the change in length of the chords, the truss will distort.

The results vary. If doors are jamming, then the doors do not have headers over them. If it is drywall construction, there should be cracks in the drywall and possibly nails popping as well.

Of course, the house could also have a high humidity - look for ice on the inside of the windows - in which case the wooden doors may be expanding.

http://www.buildingscience.com/documents/reports/rr-0107-drywall-wood-and-truss-uplift

Posted by: gus on January 17 2009 8:13 PM

The best reason for shovelling portions of roof that have a lot of snow on them in the winter is to reduce the likelihood of ice damming.

While there have been no reported residential roof collapses in PG while I have lived here over 35 years, water damage to roofing, exterior walls and in the worst cases interior walls and ceilings due to ice damming is considerable.

Posted by: gus on January 17 2009 8:15 PM

BTW, houses in Canada are really not well designed for winter conditions. They are designed for California conditions.

Posted by: beesknees on January 18 2009 5:54 AM

OK, I've read all the comments till now, and I'm going to preface my one and only comment on this matter by saying that I am an authority on this subject, and my knowledge and experience should not be questioned. So here's my opinion:

You don't have to shovel off your roof. If you want to shovel snow, come over to my place and shovel off my driveway.

There, that should end this discussion, for once and for all.

Oh, and our Chief Building Inspector is not an idiot; people in his position are generally quite intelligent, and have been promoted because of their experience.

OK, now I'm really done.

Posted by: Outwest on January 18 2009 9:15 AM

If inside Wall would be build like supporting Walls including proper size Door Headers you never have to worry, but if the Builder saves on Lumber you are in trouble, it's all like "Gus" said build Headers over Inside Doors and they will open and close any time.

Posted by: lostfaith on January 18 2009 2:56 PM

You mean like Gus's quote :)