Need Roof, Have No Plans

SansPlans · September 07, 2007, 10:58:00 PM

It is a harbor freight gun I got for 50 bucks. It has worked great. http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=93912 It is like this one except mine adjusts for different degrees, though I keep it at 28 degrees.

Notice how it refers to the nails as 0.113" to 0.131" instead of with D's.

if 16D is the 'standard' framing nail that is probably what I am using.

PEG688 · September 07, 2007, 10:58:44 PM

If your cuts are that bad buy a flat strap that can be nailed to the top of the rafters and run it up one rafter over the ridge and down the other side. They sell a coil strap that would be perfect for that. The collar ties you should use , and with that strap over the top say a 36 " long piece your cuts could be really $hitty and still you'd have a lot of strenght.

September 07, 2007, 11:02:17 PM

Yup that'll work.

Hey be safe OK , it ain't that hard , BUT things can get funkie fast if your not used to heights , ladders , etc . So think it through and give yourself a good "out" if it goes to $hit on ya

BTW jumping to the ground is not what I consider a "good out" .

PS Thanks Glenn

glenn kangiser · September 07, 2007, 11:05:51 PM

Manhattan would have rated well on our inspector from hell list. He had the knowledge but no tact -felt he didn't need it as god had sent him here---- . If you can't deliver your message of instruction tactfully, then people will turn you off rather than learn from your experience. He refused to learn that so I had to turn him off.

We don't have to put up with that. No power trip here for him.

glenn kangiser · September 07, 2007, 11:08:01 PM

BTW, PEG. I'm always here for you with the Depends when you need them.

September 07, 2007, 11:09:52 PM

Ok great. Now I feel better about forgoing the simpson rafter ties. I have no reason to believe my cuts will be bad; just allowing for the inevitable 'Oh my gosh, i didn't think it could be this bad in my worst nightmare but yet here it is in front of me, what do I do now?' scenario.

I will be careful; nothing can be as bad as the bond beam pour in terms of risk, pain and suffering. The pump crane operator hit me on the head w/ the boom and darn near knocked me off the wall.

So tomorrow morning I will traverse to home depot and pick up a new box of framing nails (the only ones I have left are too short I think) and give it a try w/o the rafter ties. That will save a lot of work so hopefully it will turn out ok. I have a swanson speed square and the accompanying blue book that I hope will help me make the right cuts.

I'm out for tonight. I took this whole next week off of work as vacation days to try to get as much done as I can so hopefully it won't rain all week.

Thanks again! I will update w/ pics after I get a few rafters going to see how it looks.

MarkAndDebbie · September 08, 2007, 05:29:22 AM

QuoteIf your cuts are that bad buy a flat strap that can be nailed to the top of the rafters and run it up one rafter over the ridge and down the other side. They sell a coil strap that would be perfect for that. The collar ties you should use , and with that strap over the top say a 36 " long piece your cuts could be really $hitty and still you'd have a lot of strength.

Not to say that my cuts aren't / wont be perfect

but... is that coil strap stuff like what you would find to hang pipe or ducting? or is it a heavier gauge?

Thanks

PEG688 · September 08, 2007, 09:28:27 AM

Quote

#1: but... is that coil strap stuff like what you would find to hang pipe or ducting?

#2: or is it a heavier gauge?

#1: No Simpson does not sell pipe tape , which is what your talking about.

#2: Yes ,

http://www.strongtie.com/products/cfs/cs-cmst.html

They don't show a photo of it being used as I have stated but with that strap over the top tieing two rafters together , in conjuncture with a collar tie you'd have a very strong system to resist downward forces and the spreading of walls that those forces are working on.

It will create other issue as in nailing your roof sheathing where the straps are. You'd MTL have to drill a hole thru the sheathing and the strap then drive your nail thru both at once.

Good cuts and proper nailing would be the best option.

PEG688 · September 08, 2007, 10:40:36 PM

Sans heres a example of a 1 by ridge as well as a 1by ridge that doesn't fill the whole ridge cut.

Hip roof , house built in 1947 or so, 1 x 8 , made from shiplap sheathing , ridge and 2x6 and 2x4 rafters , the rafters are over spanned even for 20 years ago , with todays wood SPF or even D Fir they'd be way way way over spanned.

This shot shows a gable roof with the 2x4 rafters and a 1x8 ridge ,

Jack rafter dieing into a hip ridge , note the 3 ea. 16 d bright nails , in those days brights where the framing nail of choice before the Ca. boys started the "gas and wax' 16d which the modern day sinker was developed after.

Things to notice are the cuts where good and have stayed good. Even the rafters that are not supported all the way on the ridge cuts still look like they did 60 or so years ago.

No collar ties , but remember this is a hip roof so downward pressure is spread / shared differently than a gable roof . A hip is considered one , if not the strongest roof lines.

They also used 1x 6, 8 , &10 shiplap for sheathing on the walls , floors and roof. So of those boards where used on the foundation as concrete staining can be seen on them.

September 08, 2007, 10:47:07 PM

Thanks for the pix, PEG. You mentioned that the old boards were over-spanned. Did you notice any sag in the roof?

PEG688 · September 08, 2007, 10:54:21 PM

Oh ya it's sagged some , it's my roof , it's strong enought , the rafters have just sagged some. Feels fine when you walk on it but yes they have some sag.

glenn kangiser · September 08, 2007, 11:05:23 PM

Thanks -- just wondering. Our other house -- a real house -- not a cave, has sagged a bit -- a hip roof also built in 1952. Also - not a problem. Redwood siding all around the original part.

SansPlans · September 09, 2007, 02:49:32 PM

Ok guys, I'm having trouble. I used the swanson speed square blue book thing, to calculate the rafter cuts.

It turns out my building's span is 39' 6.5" instead of 39'. hee hee my mistake.

If I use the blue book table values for 39' + 6", do I need to worry about the 1/2" of span not being accounted for? I cut two rafters based on 39' 6" and they aren't really fitting but it seems like 1/2" isn't in the blue book and would be so miniscule that it wouldn't make as big of a difference as I am experiencing.

When I try to put the rafters up, do I nail them to the ridge first and then the joist, or vice versa? Nothing is really adding up and I can't tell if they are too short or too long or what the problem is. If I nail one to the ridge board and the joist and get it to the right rise height, it looks fine w/ no gaps. Then I try to attach the opposing rafter and it has to be pushed back toward the top-plate (making the birdsmouth not on the top plate hardly at all) in order to match up to the ridge board.

I tried to be very careful w/ the calculations for the 4/12 slope, 39' 6.5" span but I must have made a mistake somewhere. Can someone check me?

Here's what I came up with.

Rise: 6' 7"
Rafter length:20' 10"
I remembered to take out 3/4" to accommodate half the width of the ridgeboard, so that makes the rafter length 20' 9 1/4".

the little angle thingys I followed the blue book and am pretty sure I did those right. I think the degree angle was something like 19.5.

I just went up again and took the ridgeboard out of the picture altogether, and the two rafters overlap eachother by about 1 1/2". birdsmouth and angles all look fine except the rafters just seem too long. I guess I could just cut them but it seems like I should be able to figure out why they are longer than they should be. Also I don't want to cut up my $900 dollars in rafters and find out I did something wrong.

PEG688 · September 09, 2007, 04:40:51 PM

Sounds like you did NOT reduce for the ridge thickness. 1 1/2" ridge = reduce by 3/4" on each rafter.

September 09, 2007, 06:09:35 PM

I am sure I did. I even rechecked calculations and re-measured my template. They are overlapping eachother by 1 1/2", so if I trimmed 3/4" off each, they would be even w/ eachother, and there still would be no room for a ridge board.

I think my angles are all a little bit off or something. I rechecked my ridge board angle and it was a little bit off. This accounts for the gap shown in the picture of the rafters connecting to the ridge board.

I ended up pushing the two rafters up into the air, pivoting off the seat cut until there was a 1 1/2" gap between them. It worked out ok I guess, everything has a little bit of a gap but I guess it is close enough. The seat cut is off the top plate a little (from lifting the rafters higher to eliminate them overlapping so much that the ridge board wouldn't fit between them), but I figure maybe it can just droop down over time.

Can you check out the attached picture and tell me if this is cause for concern? I intend to adjust my template a little bit on the next two rafters and see if I can get it closer. If it doesn't make an appreciable difference then I'll just cut all the rafters at once. haha At this rate it will take me 50 days to do my rafters! Hopefully I can become more efficient on the next few.

By the way, the line that you see on the seat cut is from an old measurement, it wasn't the line I was cutting off of. That seat cut is a little mangled because I had to yank it out and it ended up splitting it a bit...maybe closing the gap a little! Also, "Rafter 2" looks like it is too high above the ridge board but that is because the ridge board had a big bevel on that edge.

Edited to move image to photobucket - GK

PEG688 · September 09, 2007, 08:28:57 PM

So to be clear you only have two rafters cut right now?

Where did you measure ? There is a thing called the "measuring line ? maening you need to measure parrell so you need to measure from the crotch of the seat cut to a point the same distance from the rafter bottom.

It's hard to explain that measuring line thing .

Do you have a steel square ? I helped youngins with his little roof and wrote and provided photos on how to "step off" rafters. I never measure mine , but I do check that number after I step off the rafter, just to compare the two.
Check out yougins thread about putting a roof on or some such.

Generally I check one pair of rafters at each end of the building if I like the look the first one I layed out becomes a pattern , I choise a good straight rafter to lay out first thing and make it as "Pattern".

How does the building measure up ? Is it the same exact measurment on each end ? If it is once your happy with your rafters cut them all , you can move the ridge to where it needs to be that way.

If your building is all over the place in size / measurment , your screwed I can't explain how to fix that.

SansPlans · September 09, 2007, 10:11:33 PM

Just two rafters are cut right now...well, three. Two are up on the house and one is my template. I think I have 8 extra rafter boards to burn through before I will be short. My building is the same span on both ends fortunately. However the plate that I bolted onto the top of the block wall swerves a little due to warping but but it should be well under 1/2" variance.

I searched for but could not find the 'youngins' thread about putting a roof on. Can you post a link if you are able to find it?
I think I know what you are talking about. where you don't measure the rafter but hold it up and trace the marks? We did that on my daughters tiny 4' high play house. I didn't think to try that in this case because the rafters are so long and I'm working by myself so I wasn't sure if I would be able to hold it exactly right to make the marks.

I do have steel square (and an aluminum one too!)

Did the pics I posted look like they were within acceptable tolerances in terms of gap? It didn't look that bad to me except I keep seeing everyone elses perfect rafter pictures!

I am going to try to adjust my angle a little to fill in some of that gap. Basically All I did to get it from overlapping 1 1/2" to having that small gap was just pushing the rafters up. If the gap is ok, I will just continue doing what I'm doing and make some adjustments as I go to try to make it smaller. The gap I think was like 1/4". The rafters are 16" oc in case that information factors into what is acceptable.

MountainDon · September 09, 2007, 10:30:58 PM

Looking at the Birdsmouth and seat photo.... You should cut to the line with the circular saw and then finish the cut off with a jig saw, sawzall or hand saw to avoid that strength sapping over cut.

PEG688 · September 09, 2007, 10:31:23 PM

Here's that link

http://www.countryplans.com/cgi-bin/yabb2/YaBB.pl?num=1185561119/0

I think

#1: are you sure your birds mouths are up tight to the wall? If they are not pull up on the ridge would close both gaps , the BM and the ridge cut. '

#2: if your up tight I'd take a saw cut from nothing at the bottom to 1/8" , maybe a touch more at the top , to fair that cut in. If you did that you'd be lookin real good.

#3: Your cut , as they sit arn't that bad , BUT things like that tend to grow , not get better . So the beter the first pair look , the better they all will look in the end.

#4: I'd try step #2 above before you do anything else. I think that might solve your issue.

MountainDon · September 09, 2007, 10:36:54 PM

Youngins roofing thread

http://www.countryplans.com/cgi-bin/yabb2/YaBB.pl?num=1185561119

September 09, 2007, 11:24:14 PM

Thanks guys. I will workwith it some more tomorrow and hopefully get it closer. I'll post some pictures tomorrow of the perfectly fitting rafters I'm anticipating.

I was wondering about the overcuts myself too. I will try to get a hold of a hand saw to avoid them. I didn't like them either but didn't realize it would sap an appreciable amount of strength from the board.

SansPlans · November 14, 2007, 09:56:01 AM

Forgot to update w/ the results. Turned out pretty good although it was plenty time consuming for me to do it by myself.
We got carried away and added another room up top because we had lots of wood laying around we had already paid for.

Thanks everyone for all your help.

glenn kangiser · November 14, 2007, 10:19:37 AM

Looks good. Looks like the top room may like some rafter ties or something to keep the walls from pushing out sideways.

SansPlans · November 14, 2007, 10:23:55 AM

Well, I glued up a beam for the top room hoping that the rafters would just kind of hang on it instead of pushing on the walls. The reason is head room. Do you think that w/ 2x6 w/1/2"plywood glued/nailed into a beam that it will spread? That would be scary. The beam is like 12 or 13' across so I was hoping maybe that the beam would be stiff enough to not allow rafters to spread walls.

Here is the beam in this pic. I slathered some more weatherproof titebond on the top to help protect it from weather.

glenn kangiser · November 14, 2007, 10:38:53 AM

What I think I see in the picture is that the ends of the beam don't go to a solid ground support -- all the way down -- so it can still sag.

If you could put collar ties a bit down without destroying your head room that would help -- they are shorter and higher than rafter ties. You could gusset the collar ties to make it more of a truss giving more of the strength of the rafter rather than pushing and spreading by shoving against the ridge beam.

Sheathing the endwalls and nailing as for brace panels could also help with the beam support, but for it to work the load needs to somehow transfer to the foundation and ground. Posts would be ideal but maybe not possible due to what is below. Filling in the open spaces with posts could transfer the weight to your block wall on the end it looks like.

Gluing the plywood gussets at the collar ties will help also. Making them as big as possible will also help.

Maybe I'm being overly cautious but it looks like an issue worth taking care of to me.