Cutting bevelled siding joints at a 22 1/2 degree angle

[check]

Hello guys, here is one for you. I am installing beveled siding on the garage, and the siding supplier (Maibec of Quebec) says to join boards by cutting them at a 22 1/2 degree angle, to prevent water penetrating the joint. (As opposed to just 90 degree but joints.)

They also say to cut the 22 1/2" joints with the "visible" side facing down, and my friend who is helping me says he can't measure properly that way. The problem, of course, is that the cut at front (flat) side of the siding will be at 90 degrees, but the back (beveled) side will not. So, he is cutting the other way, but that makes the joints at the front slightly off of 90 degrees, which is I suppose acceptable, but it does look a bit funny.

View attachment Siding Joint Maibec siding.pdf

Any advice here would be much appreciated!

 

[AWSubie]

You take a piece of scrap and cut the bevel and then measure how much longer (or shorter depending on whether you are cutting a left or right bevel ) the back side is relative to the front side at the bevel. Then add the difference to each measurement. Also check to be sure your saw blade is square to the backrest and plumb to the table surface.

 

[davedj1]

I've been a builder my entire life (60 now) and never had any need or want to cut the bevel siding at 22.5 degrees. Cut it square, it should have a caulk joint anyway as wood comes and goes with the weather. We install mostly preprimed stuff now so we spray some primer on the cuts to seal it up. What type of wood is your siding?

 

[downsizingnow48]

I've been a builder my entire life (60 now) and never had any need or want to cut the bevel siding at 22.5 degrees. Cut it square, it should have a caulk joint anyway as wood comes and goes with the weather. We install mostly preprimed stuff now so we spray some primer on the cuts to seal it up. What type of wood is your siding?

ditto. Even 30 years later I have looked at siding jobs and cannot see any problem with a square joint caulked. That sounds like a engineer who has never done anything except read books.

 

[Billrog]

I've always cut siding at 22.5 degrees rather than butt joint looks more professional hides the joint from the side most viewed. But it's been years since anyone has put wood siding on around here due to the maintenance factor and hard to get fire insurance in the country side.

 

[chim]

I've seen horizontal cuts made on a bevel, and some even had flashing in the joint. Never really paid a lot of attention to vertical joints. My guess is that Maibec either has (or thinks they have) a real reason.

As far as the installation, I'm not a carpenter so I don't understand the problem. Aren't the very ends of each run cut at 90 degrees to butt into the trim? Any reason that 90 degree cut couldn't be made last? Not the best drawing, but three pieces working from right to left:

l-------//--------//----------l

Or left to right:

l---------\\----------\\--------l

 

[check]

I've seen horizontal cuts made on a bevel, and some even had flashing in the joint. Never really paid a lot of attention to vertical joints. My guess is that Maibec either has (or thinks they have) a real reason.

As far as the installation, I'm not a carpenter so I don't understand the problem. Aren't the very ends of each run cut at 90 degrees to butt into the trim? Any reason that 90 degree cut couldn't be made last? Not the best drawing, but three pieces working from right to left:

l-------//--------//----------l

Or left to right:

l---------\\----------\\--------l

Well, it's all finished now, but the issue is that bevelled siding cuts different than flat siding, depending upon whether the face is down on the mitre saw, or the back side is down. If you cut with the face side down at, say 22.5 degrees, the face side of the cut is perpendicular to the length of the board no problem, but if you cut with the face side up, the back side is perpendicular, but the face side is off a bit. It is in fact hard to see this after application if no one points it out to you, but you need to make sure that the matching cut is laid out on the OPPOSITE side of the saw, so that slight angle matches.

Weird. Makes sense when you think about it, but I would have never thought of that ahead of time.



PS That is my helper, holding the little Ryobi 18 volt circular saw that I gave him after we were finished. (He like it a lot, and I had 3 of them so...)

 

[chim]

Now I get it. Several years ago I had a challenge cutting angle iron for target frames at the range. Fortunately another member was a machinist and it was a piece of cake for him on his Jet saw..

Very nice looking project. Battery tools have come a long way since I used a 6V Black & Decker drill back in the early 70's.

I'm working on a new shed for the tractor and trying to get it done before the weather gets bad. I've been using a DeWalt 7-1/2" 20V circular saw for most of the straight cuts on 2x4's and for ripping sheets of plywood. Angle cuts for the trusses were mostly made on the 120V 12" miter saw. For the really sharp angle needed twice per truss on the top chords I made a jig that went over the 2x4 for the battery saw. I'm good for a day with a few 5AH batteries.

 

[3Ts]

The reason for the angle cuts has to do with aesthetics. Wood moves, primarily across grain and there is always some fitment challenges during construction, so if the joint is cut at an angle it will be harder to see than one cut at 90*. I've always used 45*, but no reason 22.5* shouldn't work just as well, You'll lose less material.

As for 90* joints up against trim or corner boards. If you want a really good fit, use 88*. This means a lot more labor which is why it isn't used much, but you won't see a gap. (It should still be caulked if on the exterior)