# Identification and cutting of roof truss system for skylights?



## ChrisDIY (Feb 1, 2010)

Something like this which will require cutting that center joist.


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## Gary in WA (Mar 11, 2009)

Yes, those are trusses. NO, can not cut them.

Gary


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## Ron6519 (Mar 28, 2007)

I don't see any trusses, just engineered joists.
Ron


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## Scuba_Dave (Jan 16, 2009)

Post a better pic of whats up in the attic for a rafter system
Could be engineered I-joists ?


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## Gary in WA (Mar 11, 2009)

The first picture sure looks like a fink truss with the lower end web behind the white plumbing vent under the blown-in insulation....... Turn your head clockwise 20*, you're looking up through the ceiling. The osb rakes down to the left outside wall.

Gary


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## ChrisDIY (Feb 1, 2010)

Scuba_Dave said:


> Post a better pic of whats up in the attic for a rafter system
> Could be engineered I-joists ?


This space is much larger than 30 sq. ft. length is somewhere between 18-23 ft. by 6-8 ft. So 108-184 sq. ft. :furious: In order to remedy a problem was hoping could break up with skylights...:surrender: If the space between trusses is greater than 16 o.c. which it looks like, have to get ladder in and actually measure. Can I or someone frame onto side of truss to make the channel? Can get as narrow as 14" x 45 skylight???


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## Gary in WA (Mar 11, 2009)

If the trusses are 2' on center, (as they appear), install a skylight between two, as is the norm. It doesn't have to be centered in the room, just install the fan next to it. 

"I would like to put a skylight above the shower to reduce the volume of space to within code." ---- Could you explain this more, please? 

Gary


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## Tom Struble (Dec 29, 2008)

skylites in the bathroom look so pretty in the pictures,but with the anount of possible condensation they can sometime be a real problem


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## ChrisDIY (Feb 1, 2010)

GBR in WA said:


> If the trusses are 2' on center, (as they appear), install a skylight between two, as is the norm. It doesn't have to be centered in the room, just install the fan next to it.
> 
> "I would like to put a skylight above the shower to reduce the volume of space to within code." ---- Could you explain this more, please?
> 
> Gary


Unless I am misreading (don't have printed source, only online) any attic space larger than 30 sq. ft. needs access.


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## ChrisDIY (Feb 1, 2010)

This is my framing plan since I need to provide support for drywall etc. I will need to do this 4 times along the space. Once over this bathroom and twice over center of adjacent bathroom and maybe the fourth over the new master shower, but very reluctant since this shower will get heavy use.









*tomstruble* can you go more in detail about condensation issues? On skylight or walls?

Planning on using this shower door.


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## Scuba_Dave (Jan 16, 2009)

Hot steam/water vapor rises & will condense on the cooler surfaces
That will usually be the skylight
I take fairly long, hot showers at times & the water vapor condenses on every wall in my bathroom & the ceiling...no skylight

So even without a skylight you can have the condensation issue
A good fan will help get rid of the mositure
My bath fan is around 110 cfm, bathroom is round 330 cf
I have skylight in my 2nd floor bath
But we do not use the shower that much
I like the light in the bathroom


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## slickgt1 (Apr 1, 2010)

How about installing a velux suntunel? One, the deflector is far away from the bubble on the roof, so the deflector will stay at room temp., no condensation Two, you do not need to worry about the rafters. The tunnels are 14" wide at most. I can tell you from first hand experience that these give off so much light, that during the day, there is no point to turn on the lights in the bathroom. 

Other option, leave the rafters, get a 48" skylight, decorate the rafters, and run sheetrock down and around them. I have done this too. 3 times in the last 2 years actually. Let me know if you want some pics.


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## ChrisDIY (Feb 1, 2010)

slickgt1 said:


> How about installing a velux suntunel? One, the deflector is far away from the bubble on the roof, so the deflector will stay at room temp., no condensation Two, you do not need to worry about the rafters. The tunnels are 14" wide at most. I can tell you from first hand experience that these give off so much light, that during the day, there is no point to turn on the lights in the bathroom.
> 
> Other option, leave the rafters, get a 48" skylight, decorate the rafters, and run sheetrock down and around them. I have done this too. 3 times in the last 2 years actually. Let me know if you want some pics.


Can you attach sheetrock directly to trusses?


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## slickgt1 (Apr 1, 2010)

dawktah said:


> Can you attach sheetrock directly to trusses?


Yea why not. I've done it, and seen it done countless times.


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## slickgt1 (Apr 1, 2010)

ill get you a pic to explain


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## slickgt1 (Apr 1, 2010)

You can see what I did. Sheetrock is not really attached to the trusses, its attached to the framing around them, but you can see them through that opening. I didn't cut any of them out. I polyurethane-d the hell out of the trusses, and they look like furniture. 

Sorry for the crappy pic, but its the best I have on hand.


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## Michael Thomas (Jan 27, 2008)

I second the light-tube suggestion.


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## Gary in WA (Mar 11, 2009)

Are the skylights to reduce the attic space below 30sq.ft. to eliminate the required access? Would the solar tubes be too small to reduce the square footage enough? 

Yes, you can drywall directly to the trusses, just don't attach to the wall drywall for cracking there: http://www.buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange/

I've installed an additional smaller bath fan in the skylight chase near the top to remove air before it condenses there. 

Skylights will get warm at the top area, enough to melt snow and cause an ice dam, I&W shield is your friend: http://www.homeenergy.org/consumerinfo/roofs.php http://docs.google.com/viewer?a=v&q...nlqADl&sig=AHIEtbTCLG7Hu88F_xfrMubvjsQrLkvXfw Use some foam board under the drywall to keep the heat in the chase and not warm the roof framing. Insulate the chase well: Page 31: http://www.nybtg.com/downloads/thermal_bypass_checklist.pdf

Gary


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## ChrisDIY (Feb 1, 2010)

GBR in WA said:


> Are the skylights to reduce the attic space below 30sq.ft. to eliminate the required access? Would the solar tubes be too small to reduce the square footage enough?
> 
> Yes, you can drywall directly to the trusses, just don't attach to the wall drywall for cracking there: http://www.buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange/
> 
> ...


Awesome!


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## ChrisDIY (Feb 1, 2010)

Well after looking at things I have yet another hurdle. The soil stack is right there and if any of the skylights are to open I need 10' clearance? So if they are fixed and do not open is it still a done deal?


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## Gary in WA (Mar 11, 2009)

*Vent Termination
* Roof--min. 6in. above {and 12in. to vert. surface} . . . . [3103.1] {906.1}
Clearance to building openings-2ft. {3ft.} above OR
10ft. horiz. [or 4ft. below] . . . . . . . . . . . . . . . . . .T-m2 [3103.5] {906.2}
Sidewall vent--min. 10ft. from PL and 10ft. above grade [3103.6] {Ø}
From: http://www.codecheck.com/cc/pg13_14plumbing.html

Gary


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## ChrisDIY (Feb 1, 2010)

GBR in WA said:


> *Vent Termination*
> Roof--min. 6in. above {and 12in. to vert. surface} . . . . [3103.1] {906.1}
> Clearance to building openings-2ft. {3ft.} above OR
> 10ft. horiz. [or 4ft. below] . . . . . . . . . . . . . . . . . .T-m2 [3103.5] {906.2}
> ...


Thanks!

Now I'm worried that the angled run in that vent pipe is even code. All pics of soil stack I can find are straight vertical.


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## Gary in WA (Mar 11, 2009)

Try a new post question on the "plumbing" section. I believe it depends on which Code you are under locally.

http://www.co.lincoln.wa.us/Assessor/Building/Top 10 plumbing mistakes handout-4-09.pdf

Gary


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## mrgins (Jan 19, 2009)

You CAN apply DW directly to trusses, but I prefer to strap the trusses first. You can also cut trusses but there is a special way to do it and you'd need an engineer to approve it.
As suggested, why not use a Sun Tunnel. You can get them with built in lights for night time use. A skylight in a bathroom is asking for condensation trouble.


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## ChrisDIY (Feb 1, 2010)

mrgins said:


> You CAN apply DW directly to trusses, but I prefer to strap the trusses first. You can also cut trusses but there is a special way to do it and you'd need an engineer to approve it.
> As suggested, why not use a Sun Tunnel. You can get them with built in lights for night time use. A skylight in a bathroom is asking for condensation trouble.


My primary use is not for light but as a partition to separate the attic space above.


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## slickgt1 (Apr 1, 2010)

dawktah said:


> My primary use is not for light but as a partition to separate the attic space above.


Correct, put the Sun Tunnel, and box off the tunnel in the attic. That will give you separation.


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## ChrisDIY (Feb 1, 2010)

slickgt1 said:


> Correct, put the Sun Tunnel, and box off the tunnel in the attic. That will give you separation.


If I do Sun Tunnel will I need to move the stack vent?


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## slickgt1 (Apr 1, 2010)

dawktah said:


> If I do Sun Tunnel will I need to move the stack vent?


Well the sun tunnel has a flex duct, so you can move it far enough to be within code with the vent.


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## HitLines (Aug 31, 2009)

I agree with the sun tunnels but they look more like recessed lights than a skylight. I plan to install two of them for my dark hallway. No reason to flip on a switch for 20ft.









http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053


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## slickgt1 (Apr 1, 2010)

I only installed the velux ones, but yea, they are great. You can buy the light kit for it, so that you can turn on the lights at night. You actually get the glow of the moon at night too. I love them, i have 3 down my hallway. Before it used to be dark, and you always needed to turn on the lights. Now I only turn on the lights at night only. Love it.


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## ChrisDIY (Feb 1, 2010)

Does anyone make one that is designed for a north roof pitch? Anything is an improvement over the cave this bathroom is, but any with angled reflector to catch southern sun?


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## slickgt1 (Apr 1, 2010)

dawktah said:


> Does anyone make one that is designed for a north roof pitch? Anything is an improvement over the cave this bathroom is, but any with angled reflector to catch southern sun?


Get yourself the flex duct one, and you can turn the bezel inside to whichever exposure you want. You will understand once you get it. Or go to velux and find the installation instructions, they have pictures of what I'm talking about.


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