Calculating ridge angle cut [Archive] - Home Construction Forums

Jackhammer

02-23-2005, 07:11 AM

I'm sorta confused. I ran across this thing called "Easy Rafters" that is suppose to compute everthing for you but somethin ain't right compared to http://www.construction-resource.com/roof-frame.php.

Easy Rafters show the common rafter to be 9'9" including 1' overhang with a 67.38 angle at the peak.

The other shows the common rafter to be 9.75' with a 22.62 angle.

Without going thru all the mumbo jumbo mathmatical equations can you tell me which of these are correct?

Jackhammer

02-23-2005, 08:45 AM

Is anyone understanding what i think i'm hearing or is the water so murky the fish can't see where they have been.

I know Joe has to have an answer for this....

Rich, what did I miss???

Joe Bartok

02-23-2005, 09:06 AM

I'm not having any luck following the second (Easy Rafter) link, but why not use the calculator Rich posted?
http://www.construction-resource.com/roof-frame.php
Enter: Roof Pitch = 5
Nominal Ridge Width = 1.5
Plan Distance = 8
Overhang = 1
(Rich, or anyone else: Correct me if I did that wrong!)
Here's what it returns:
Rafter Length = 9.682' (9' - 8 3/16")
Main Rafter Miter Angle = 22.620°
This is based on a run of:
8' + 1' - .0625' = 8.9375' (8' - 11 1/4")
(The .0625' subtracted is half the ridge thickness ÷ 12)
The rise will be:
3.72396' = (3' - 8 11/16")
The 67.38° angle in your last post is the complement of the Main Rafter Miter Angle.

Jackhammer

02-23-2005, 09:19 AM

Thanks for the reply Joe. Heres what I gots. I did use the link that Rich provided however the Easy Rafter calculation was different.

The Easy Rafter link shows the rafter to be 9'9" and I was wanting to make sure which of the two was correct.

What does the complement of the main rafter miter angle mean? Is it the same as the 22.62?

I'm thinkin I may just stick to buildin' bird houses.

Sorry about that link I guess I was asleep.

Joe Bartok

02-23-2005, 09:27 AM

Jackhammer

02-23-2005, 09:41 AM

Thanks Joe, that makes sense. Rather than using a ridge board on an 8' run would it be possible to use gussets and collar ties?

Joe Bartok

02-23-2005, 10:04 AM

learning, I've been missing a lot of posts recently and "speed-reading" others, and I just noticed today that in the "Angles on Gambrel Roof" thread, you said you don't intend to use a ridge board.
I can only give you the same answer everyone else did in the "Ridge Beam Length" thread: Any log or timber framed roof I've ever been involved with always had a ridge member.
Why? Ever noticed the ridgelines on old, abandoned buildings while driving along a country road?

Jackhammer

02-23-2005, 10:14 AM

Thanks to everyone I will be using a ridge board...

What would be the best method of erecting a 20' ridge board? If I have a 1' overhang on the sides I suppose I would also need an overhang on the ends. In that case would I need a 22' ridge board?

Rich

02-23-2005, 03:37 PM

Great posts Joe ..
I was going to say to learning that 9'9" is equal to 9.75' :) and then all the other stuff regarding the complementary angles.

Cole

02-23-2005, 03:57 PM

Jackhammer

02-23-2005, 06:16 PM

Cole

02-23-2005, 06:18 PM

Jackhammer

02-23-2005, 06:46 PM

Hey Mr. Cole, how would be the best way to hold this thing in the air while the rafters are being nailed to it? Does the board need to be 22'?

Sorry for the cornfusion...

Cole

02-23-2005, 06:53 PM

Is it just going to be you, doing this?

Jackhammer

02-23-2005, 07:51 PM

Just me, myself and I. Is that not a crew?

I figured I could hold one end while myself held the other and me could nail the rafters on. LOL

Is it possible for one person to attempt this and if not what would be the best method?

Cole

02-23-2005, 07:55 PM

Figure out the height to the top of the ridge off of the floor or the top-plate, And cut a 2x4 deducting the height of the ridge from it and just stick it under both ends of the ridge.

Jackhammer

02-23-2005, 08:00 PM

Thanks again for your patience. I'm going to get this right if it takes me for ever.

Do I become a developer when I aquire 500 posts? LOL

Cole

02-23-2005, 08:06 PM

Lol, I think it is something like 100 maybe.

Joe Carola

02-23-2005, 09:03 PM

Learning,

If you use a 2x6 ridge which would be fine for what your doing you can set your two posts up first so that they will be right underneath the ridge with a 2x4 bracing it up plumb both directions.

Since you might be by your self on one side of the first post you can tack in a 2x4 around 6-7" higher then the top of the post so that when you sit your ridge on top of the posts it has something to lean up against. On the other post you can do the same thing but tack the 2x4 on both sides so that when you lift the ridge up it will slide into a pocket and then you can go down to where the single 2x is and nail the ridge in place and the other side won't move because it's in the pocket.

Now you can take your one rafter and start on the first 16" center mark and nail the top of the rafter at the ridge 16" center mark and then go down and nail the birdsmouth in making sure it's tight to the plate.and do the same on the other end and then do the same on the other side.

Once you have the 4 rafters set into place you can go and nail a rafter every 4' but nailing at the birdmouth first and go on top and nail at the ridge then go on the opposite side and nail the rafter in. Nailing the rafters evry 4' on both sides keeps the ridge from bowing if you were to nail one side first that would happen.

I drew a picture for you with the measurements and the post height. I hope this helps.

Cole

02-23-2005, 09:06 PM

thank you for fully explaining it, i just didnt feel like writing that much. hehe

Learning: follow Joe's instructions.

Dragon

02-24-2005, 05:28 AM

thank you for fully explaining it, i just didnt feel like writing that much.

Ditto

Jackhammer

02-24-2005, 06:03 AM

You guys are a life saver.... Thanks a million and keep up the good work

Jackhammer

02-26-2005, 06:02 AM

The complement of an angle is 90° - Angle.
In this case, 90° - 22.62° = 67.38°.
If you draw a triangle to scale to represent your roof in section, you'll find the 22.62° occurs at the foot of the rafter, and 67.38° at the rafter peak.
(By the way, go ahead and laugh, but I've actually used this math in the past to build bird houses and bird feeders. Not much money in it, but it's fun, and it's an inexpensive way to try out miter and bevel cuts I'm uncertain about). :)

Joe, got another question. You mention the 22.62 degree occurs at the foot of the board and the 67.38 at the rafter peak. Does this mean the rafter should be cut at the 22.62 at the end by the birds mouth and the peak at 67.38? I'm sorta confused here because my miter saw doesn't cut at 67.38, it only represents 50 degrees. What am I missing AGAIN?

Joe Bartok

02-26-2005, 07:49 AM

learning: This is just a quick sketch, not to scale, showing the angle locations. As noted on the drawing, any angle you measure with respect to level will be 22.62 degrees, angles with respect to plumb are complementary, 67.38 degrees. Hope this helps.

Jackhammer

02-26-2005, 08:01 AM

Ok Joe, I apoligize for my ignorance but in your diagram it states "angles measured with respect to plumb" are the same for both angles. Not being much of a carpenter I'm having a hard time understanding this. I guess I'm just plain hard headed.

So if the 22.62 is at the birds mouth how do I get a 67.38 degree cut at the ridge? Do I have an obsolete miter saw?

Rich

02-26-2005, 08:07 AM

Flip the rafter over and cut a 22.62 :)

Jackhammer

02-26-2005, 08:11 AM

Rich, do you mean at the ridge?

Joe Bartok

02-26-2005, 08:15 AM

Someone else can probably explain this better, but I'll try.
To cut 67.38 degrees at the ridge, you would place your rafter against the saw fence, set you miter on the saw to the 22.62 degrees, and cut. This will leave an angle of 67.38 degrees on the rafter (measure it).
To cut the 22.62 degrees for the bird's-mouth, all I can suggest there is to lay it out on the rafter and cut it with a hand-held saw.

Jackhammer

02-26-2005, 08:17 AM

Boy, I'll bet you guys are sick of my questions and I'll try and shut up for awhile.

Thanks a million for all your HELP..........

Joe Bartok

02-26-2005, 08:33 AM

Don't worry about it. Everyone has to start somewhere.
I'm kind of used to questions anyway. Sometimes it's consulting for the local log builders. Or coaching young folks on college equivalency tests, or tutoring math or physics.
Number one "Joe" rule: If you don't understand, ASK.

Jackhammer

02-27-2005, 09:33 PM

Hey Joe, I need your help again. I worked with the measurements you provided but I must be doing something wrong. Let me explain........

Rather than using the 2X6 indicated in the drawing for the ridge I decided to go with a 2X8.

In doing so I reduced the support post from 3' 2-11/16 to 3' 1-13/16" to accommodate the additional 1-1/2" width of the 2X8. This maintained the distance from the top plate to the top of the ridge board at 3' 8-3/16" as indicated.

Rafters were cut at the specified dimensions as shown in the drawing. The birdsmouth cut was a perfect fit on the top plate.

The problem arose when I tried to connect them to the ridge board. If the top of the rafter is held to the top of the ridge board there is about a 3/4" gap where they should meet on both sides.

I have double checked all my measurements and they appear to be correct. What am I doing wrong???

Any and all advice will be welcomed....

Joe Bartok

02-28-2005, 07:13 AM

learning, sorry I don't have a lot of computer time today. I took notes of the measurements you posted, and will get back tomorrow. (Hopefully with an answer can make heads or tails of this).

Joe Bartok

02-28-2005, 08:17 AM

In doing so I reduced the support post from 3' 2-11/16 to 3' 1-13/16" to accommodate the additional 1-1/2" width of the 2X8.
Hey, hang on a second! What "additional 1-1/2"??? We already accounted for the ridge board in the initial calculation. If I'm not mistaken, this looks like it was subtracted again. The 1-1/2 inches divided by two gives 3/4 inches, exactly the amount you are out.
Here are the numbers again:
8' + 1' - .0625' = 8.9375' (8' - 11 1/4")
The .0625 highlighted is 3/4 inches (half the ridge width) divided by 12 to convert inches to feet. So, that's 8 feet of run plus 1 foot of overhang minus 3/4 inches of ridge board.

Jackhammer

02-28-2005, 08:30 AM

The 1-1/2" I'm referring to is the additional thickness, width, or what ever it's called of the 2X8 vs the 2X6.

The width of my 2X6 is 5-1/2" vs the 7" for the 2X8.

The 2X8 reduces the height of the support board in order to maintain the 5/12 pitch. Correct??

Joe Bartok

02-28-2005, 09:54 AM

I'm out of context. Any chance you can post a sketch? Doesn't have to be a work of art. Meanwhile I'll keep thinking about this.
EDIT: I went over and over the numbers and I'm stumped. I've made different assumptions as to what size of rafter you're using, and can't get anything to work out to the given post dimensions. 3' 2-11/16 to 3' 1-13/16" Worse, the depth of the ridge should have no bearing on lateral dimensions. (Am I reading your post correctly? We're talking about 3/4 of an inch out horizontally, right?). The ridge depth will affect the height of the post, but you seem to have made the right changes in height.
Just so I've got the correct numbers, what size are your rafters, and what's the plate width? It shouldn't make any difference, but maybe knowing these figures will help me shake something loose ...

Jackhammer

02-28-2005, 11:45 AM

The diagram you provided shows the ridge board as a 2X6. The diagram also shows the support board to be 3'2-11/16" from the top plate to the base of the ridge board. The distance from the top of the ridge board to the top of the top plate shows to be 3'8-3/16".

Here is my question.. Would it not be necessary to shorten the support board 1- 1/2" in order to maintain the same height from the top plate to the top of the ridge board as indicated in the drawing?

My support boards were cut to 3'1-3/16" but my rafters are to short even though they are cut to the measurements in the diagram.

Sorry for all the confusion, I'm beginning to think I'm missing the whole picture. Maybe I can't see the forest for all the trees or could it be that the forest is blocking my view of the trees....either way I'm cornfused...

My ridge board is 2X8. My support posts are sitting atop a 2X4 top plate.

Joe Bartok

02-28-2005, 11:52 AM

Oh-Oh! learning, I'm confused as well. :oops: Looks like I've been answering posts addressed to someone else.
The diagram you provided shows the ridge board as a 2X6.
Are you by any chance thinking of Joe Carola? The only diagrams I've provided were a rough sketches done in MS Word, and certainly none of them showed any ridge boards!

Jackhammer

02-28-2005, 12:36 PM

Sure enough... But I will take any advice you might offer.

Jackhammer

02-28-2005, 01:34 PM

Joe Carola..... I put these calculations into the "Easy Rafter" program and came up with a difference.

Your drawing indicates 3' 8-3/16" from the top plate to the top of the ridge. The other indicates the distance should be 3' 7-11/16". The remainder of the measurements matched.

Maybe this is why my rafters doesn't meet the ridge board. Could you let me know which of these two are accurate and what I might be doing wrong?

Joe Carola

02-28-2005, 02:08 PM

Learning,

Your rafters are 2x6 which should measure 5-1/2".

Your Seatcut on the birdsmouth should measure 3-1/2"..

Your Plumbcut at the top of the rafter will measure 5.958333" or 5-15/16".

Your run of your rafter subtracting 3/4" for half the thickness of your 2x ridge is 7-11-1/4".

The way I figure ridge height without using the H.A.P cut (Height above Plate) is I go from the inside of the 2x4 wall subtracting 3-1/2" from 7'11-1/4" which creates a triangle to the bottom of the top plumbcut and then I add the height of the plumbcut to that and that's your exact ridge height.

I'll show you one way using a Construction Master Calculator Trig 111.

7'11-1/4" - 3-1/2" = 7'7-3/4"

Press [Run]

5 [Inch] [Pitch]

Press [Rise] Returns - 3'2-1/4"

Press [Memory]

5.5 [Inch] [Run]

5 [Inch] [Pitch]

Press [Diagonal] Returns - 5.958333" or 5-15/16" (Top Rafter Plumbcut)

Press []Recall] [Recall] Returns - 3-8-3/16" (Ridge Heght)

Press [-] [5.5] [Inches] Returns - 3-2-11/16" (Post Height)

I've never seen a 2x8 that measures 7" before but if yours does than subtracting 1-1/2" from 3'2-11/16" would be 3'1-3/16" for your post..

With this calculator you can do anything with Trig for example the plumbcut length which you can visualize as a small triangle with a 5.5" run for a 5/12 pitch and the plumbcut being the hypotenuse of the rafter.

5/12 = [Conv] [Tan] Returns 22.61986°

5.5/22.61986 [Cosine] = 5.958333' or 5-15/16" (Plumbcut)

Rafter run 7'11-1/4" or 95.25".

95.25/22.61986 [Cosine] = 103.1875" (Rafter Length)

If your seatcut is exactly 3-1/2" and your 2x6 measures exactly 5-1/2" than your plumbcut has to measure 5-15/16" and your rafter should measure with a 7'11-1/4" run 103.1875" or 8'7-3/16" with your ridge height at 3'8-3/16"

If any of these numbers are different that will change everything..

Joe Carola

Jackhammer

02-28-2005, 07:24 PM

Joe, I'm not at all challenging your data. I'm just trying to understand these figures.

If the post is 3' 2-11/16" how does the ridge height compute to 3' 8-3/16"? That's only a difference of 5-1/2". The depth of the 2X8 ridge board is 7-1/4" which would extend the ridge height to 3' 9-15/16" if my calculations are correct.

I thought this should compute to the post height being 3' 1-3/16" to maintain the ridge height.

Is this the new math that was talked about when I was going to school several years ago?

Thanks for your understanding.........

Rich

02-28-2005, 09:27 PM

Press [-] [5.5] [Inches] Returns - 3-2-11/16" (Post Height)
Joe is showing a 2x6 for the ridge beam. The ridge height stays constant due to the same run and pitch - it's the post that needs to change... that is with keeping everything else the same.

Joe Carola

03-01-2005, 05:31 AM

In doing so I reduced the support post from 3' 2-11/16 to 3' 1-13/16" to accommodate the additional 1-1/2" width of the 2X8. This maintained the distance from the top plate to the top of the ridge board at 3' 8-3/16" as indicated.

.

Learning,

The Ridge Height is 3'8-3/16. My first drawing I used a 2x6 (5-1/2") for the ridge.and deducted that from the ridge height to get 3'2-11/16" for the post.

You changed the ridge to a 2x8 and said it was 7-1/4", if you take that 7-1/4" and subtract it from 3'8-3/16" ridge height your post should be 3'15/16" not 3'1-13/16". Your ridge is to high by 7/8" therefore making your rafters short.

3'8-3/16" - 7-1/4" = 3' 15/16" (Post Height)

You could've also just subtracted 1-3/4" from the post because that's the difference between the 7-1/4" 2x8 and the 5-1/2" 2x6 ridge.

3'2-11/16" - 1-3/4" = 3' 15/16"

I don't think your challenging my data at all and I'm more then happy to help. You have to tell me if the seatcut is exactly 3-1/2" and if the 2x6 is exactly 5-1/2" and if your plumbcut at the top is 5-15/16" and most of all is your span exactly 16'.

If your seatcut is not 3-1/2" and is more that will lower your ridge height. If the seatcut is less it will raise your ridge height.

Are you still doing this by yourself?

If you have someone to help you I'll show you a different way without any drawings or math. It's easy for me to give you the math if everything was perfect but when your out on the field nothing is perfect.

I've been framing for 20 years and I've never once set a ridge first for a gable roof we just nail the for end rafters on and then slide the ridge up into it and that sets your height but that's with help, in your case your by yourself unless you can get a pair of hands to help. Let me know.

Joe Carola

Joe Bartok

03-01-2005, 07:07 AM

Since I’m in this deep, may as well carry on and add more fuel to the fire. Yesterday morning I scribbled the incorrect numbers on a piece of paper, that’s why I couldn’t make heads or tails of anything. :oops:
I wrote down the correct numbers before signing off yesterday and did these calcs last night; hopefully this makes sense:
Converting inches to feet: 5.5/12 = .45833, 3.5/12 = .29167
2 by 6 rafter over 2 by 4 plate:
HAP = .45833/cos 22.61986 - .29167 tan 22.61986 = .375
Reference dimension from corner of bird’s-mouth = 7.9375
Rise = 7.9375 tan 22.61986 = 3.30729
Post Height for 2 by 6 ridge board = 3.30729 + .375 - .45833 = 3.22396 (3’ – 211/16”, same result as Joe C's.)
Changing the ridge board to a 2 by 8 removes two inches from this measurement, leaving us with 3’ – 011/16”.
EDIT: Having read the posts made since yesterday afternoon, I see we're using 71/4" for the ridge board, I was using a difference of two inches between the two ridge boards. The 71/4" changes the measurement by a quarter of an inch, giving a measurement of 3’ – 015/16” (as already posted by JC.)

Jackhammer

03-01-2005, 07:18 AM

Joe, and others, I apologize for the misunderstanding I generated with reference to the ridge board width.

I believe I caused alot of confusion all the way around first thinking I was going to use a 2X6. I then changed my mind and decided to use a 2X8 after reading several posts which said to use the next size up from your rafters.

I then thought the 2X8 was 7" in depth when in reality it is 7-1/4". Also I created confusion by using the term "width" when it should have been "depth". Hopefully I will get all these proper terms in order before I become a contractor. LOL

I was also being thrown for a loop trying to use the "Easy Rafter" program which has different dimensions then those you offered. With the same pitch they say the ridge height should be 3' 7-11/16". The rafter is shown to be 8' 7-3/16" to birdsmouth as your figures but shows a 12" overhang at the top and bottom of the board.

Now to answer your question. Yes, I am doing this work by myself with the generous help from you guys.

The seat was cut according to the "Easy Rafters" programs dimensions at 4-3/4" with the heel at 4". The 2X6 is exactly 5-1/2" and my plumb cut at the ridge is exactly 5-15/16". The span is exactly 16' from front to back.

I currently have my ridge height set at 3' 8-3/16" as indicated in your drawing. Maybe the seat and heel cuts are throwing everything out of proportion.

Jackhammer

03-01-2005, 08:26 AM

Joe Carola........I have thrown the "Easy Rafter" program out the window. Could you please supply me with a drawing which will indicate the exact measurements on the rafter where the birdsmouth should be cut and it's cut-out dimensions as well as the overhang? Thanks

Jackhammer

03-01-2005, 08:29 AM

The seat was cut according to the "Easy Rafters" programs dimensions at 4-3/4" with the heel at 4". The 2X6 is exactly 5-1/2" and my plumb cut at the ridge is exactly 5-15/16". The span is exactly 16' from front to back.

Joe Bartok

03-01-2005, 08:58 AM

The seat was cut according to the "Easy Rafters" programs dimensions at 4-3/4" with the heel at 4".
Someone's going to have to explain this to me as well; perhaps I'm not understanding the terms used in framing. Isn't the 4-3/4" the level measurement on the seat cut, and the 4" on the plumb?
Taking the 4-3/4" as a given, doesn't 4" on the plumb seem wrong for a 5/12 pitch? 6/12 should only give us half the measure on level, and 5/12 would be even less. I don't get it. :(

Jackhammer

03-01-2005, 09:09 AM

Joe, check this out ....http://www.easyrafters.com/

Joe Carola

03-01-2005, 09:30 AM

The seatcut is the level cut that is the width of the top plate. In your case it should be 3-1/2" for a 2x4 wall and the H.A.P. cut is the Height above Plate (Plumb) and the Heel cut is the height that is notched out .

For your 2x6 that is 5-1/2" wide with a seatcut of 3-1/2" your H.A.P. cut has to be 4-1/2". In my drawing you will see two Triangles, one is the top plumbcut and the other is the Birdsmouth. When you view things as triangles which Rafter are is makes it easier to understand how to figure them out.

I figure out the ridge height from the inside of the plate which reduces my run by 3-1/2" for a 2x4 wall because it's one less step to figure out because from the inside you have a triangle with a Run a Rise and Hypotenuse to the bottom of the rafter and add the plumbcut which is the Hypotenuse of a small Triangle.

If you want to figure the Ridge Height from the outside of the plate you will have to know the H.A.P. cut which is the Height above the plate after the Birdsmouth is cut but you have to figure out what the Heel cut is also, which is another step, like this:

7' 11-1/4" [Run]
5 [Inch] [Pitch]
[Rise] Returns - 3'3-11/16"
5.5/22.61986 (cos) = 5-15/16"
5/12 = .416667 x 3.5 = 1-7/16"
5-15/16" - 1-7/16" = 4-1/2" (H.A.P. cut)

Easy rafters gets 4" H.A.P. cut from using a 4-3/4" seatcut (Level cut) and this ia what I would get using a 4-3/4" level cut.

5/12 = .416667 x 4.75 = 1.979167" or 2"

5-15/16" (Plumbcut) - 2" = 3-15/16" which would be the H.A.P cut (Close enough)

So if you used a 4" H.A.P. cut and 4-3/4" seatcut adding it to 3'3-11/16 your ridge Height should be 3'7-11/16".

If you used all my measurements they would be wrong because I was using 3-1/2" as the seatcut with a 4-1/2" H.A.P. cut.

Here's a couple drawings I hope will help.

Joe Carola

Joe Bartok

03-01-2005, 09:32 AM

I'm opening the program now. With the "high-speed" (ha-ha!) Internet access we have here, I'll have one foot in the grave before it opens. (Can't dowload the trial version, this is the public library's computer).
For now, there's something I obviously don't understand about the seat cut, and I won't attempt any more calculations until that's cleared up.
EDIT: Thanks Joe, now I get it. The 4" is the HAP. I was taking it as the plumb measurement on the seat cut.

Jackhammer

03-01-2005, 11:29 AM

Well Joe, I remeasured the span and it is actually 16'3/16" from the front to the back. That was measuring from the outside of the top plate.

I am also using the Simpson hurricane anchors to secure the rafters to the top plate. I suppose that would add an additional 1/16" to each side since the rafters are positioned on the outside of the anchor.

What would I need to do to compensate for the extra 1/4" since the ceiling joist are already nailed in place? Would I need to lengthen the rafter or change the heel and seat?

Joe Bartok

03-01-2005, 11:49 AM

Beginning with a run of 8' - 111/4" (as returned by the Framing Calculator), subtracting the one foot overhang, adding an further 3/32" + 1/16" to the run, re-calculating the HAP (because there's been an effective increase in seat depth), and 7-1/4" for the ridge board, I'm getting a post height of 3' - 025/32".
These additions to the run are also creating an increase in rafter length to 9' - 811/32" (previously 9' - 83/16").

Joe Carola

03-01-2005, 01:19 PM

Learning,

Let's start from what you have done so far.

What is the seatcut and H.A.P cut measurements?

The length is already 8'7-3/16" from top of plumbcut to the plate. Adjusting the ridge post is not a problem. If the rafters are a little short and they're all cut thatt's not a problem either, you can always add to the ridge and use all your rafters if they're short.

Joe Carola

Jackhammer

03-01-2005, 01:58 PM

Joe, that sounds good. As it stands right now I have only cut 5 rafters. The H.A.P. is 4" and the seatcut is 4-3/4". What can I do next?

Joe Carola

03-01-2005, 04:29 PM

Learning,

With that extra 1/4" to the overall span only makes the rafter 1/8" short on each side which will not mean much. If your rafters are all nailed in already and you don't want to take them out don't worry abouit it. If you don't like it you will have to take them out and cut 1/8" out of the Heel Cut and that will slide the rafter 1/8 towards the ridge.

Now if I were you since you have a 4" H.A.P. cut and 4-3/4" seatcut adding it to 3'3-11/16 your ridge Height should be 3'7-11/16".

3'7-11/16" - 7-1/4" = 3' 7/16" (Post Height)

I would cut the post height smaller by 1/2" and set your ridge on top of that NOT NAILED and when you go to nail your rafters in keep them flush at the top by raising the ridge off the post until you've nailed your outside 4 rafters. That will set your ridge height ecaxtly were it should go. You don't even need a post under the ridge, anybody tells you you do is wrong, If you want to post under the ridge now you can because the rafters have just set the height and now you can do so.

I hope this helps so far.

Joe Carola

Jackhammer

03-01-2005, 04:38 PM

If I were to start over on the rafters and use the precut ones elsewhere do you think this would be the best. The 4-3/4" seat on these must have been meant for a 2X6 wall stud if I only need 3-1/2".

I have so many dimensions from previous posts i'm sorta getting mixed up.

I don't have any of the rafters nailed in at this time..

Boy, if I ever get a template I'll be on a roll...

Joe Carola

03-01-2005, 06:18 PM

Learning,

Here you go but make sure you cut the post shorter becasue this will help you if there's any variation with the plate. The rafter length doesn't lie if your walls are what you say they are.

This is using your 4" H.A.P. cut and 4-3/4" Seatcut.

Joe Carola

Jackhammer

03-02-2005, 04:35 AM

Joe, is the 4-3/4" seatcut I have for a 2X6 wall stud? Just curious..... The "Easy Rafter" program doesn't let you know what the wall stud is during the calculation.

I'm assuming by the drawing that you feel it would be better for me to go ahead and use the ones I have pre-cut.

Joe Carola

03-02-2005, 05:05 AM

Learning,

I don't know where Easy Rafters gets their Seatcut from but If you want to learn how to cut rafters that program wont teach you.

In my last drawing I changed the length from 8'7-3/16" to 8'7-5/16" but you can still use those rafters by just cutting out the Heel cut towards the overhang 1/8" and that will lengthen the rafter instead of wasting them and your overhang will be 11-7/8" instead of 12".

Cut one rafter and use it as your pattern and tack a piece of wood on top where the plumbcut is at the ridge and where the Birdsmouth is and that will help you flush the tops when your scribing all the rafters.

Joe Carola