Why do we still use a Birdsmouth?

[@klash6367]

I like the physical connection of the birdsmouth to the top plate, myself. The plumb cut in the birdsmouth holds the top plate secure to a degree. All the bracing and fixings do this anyway but in terms of the craft, I prefer it as a physical connection point. Birdsmouths on continuous span rafters is great if the plates dont line up or you don't want to over pack them. You can adjust the height of the cuts, keeping the top roof line consistant. It is up to the individual, but I will keep using them where applicable. Great content by the way, really glad I found your channel! Keep at it!

[@Buildsum]

Hi mate, thanks for your comment, I agree, using a birdsmouth feels like a better job and sometimes can make the construction easier if you are working by yourself.

[@omernevo5113]

in my view, apart from the better connection birds mouth provides, it also a great indicator to the straightness of your top plate, if your ridge line is true then gaps in the heal of the birds mouth will indicated the the top plate is out of position. so it serve both purposes for me. feels like it locks everything up very solid. I find it hard to believe that the same solidness will be achieved with just using tie downs, for sure they will do a great job against uplift but i reckon that eventually non birds mouth rafters will end up getting "forced" birds mouth shape at the connection point due to the roof's weight and settling down

[@Buildsum]

Thanks, Omer, the Birdsmouth certainly does help to pull the top plate into line and position it. I agree, with the surface area contacting the plate being so much less without the Birdsmouth, I think it would tend to compress more. Thanks for your comment.

[@djhago3123]

I do alot of cut roofs and always do a birds mouth but sometimes i keep it less than 1/3 especially if im doing hips and valleys so your not cutting massive birds mouths.. usually keep it 2 inches over the wall plate and then don't have to notch over block work either

[@Buildsum]

Hi mate, good to know, thanks for your comment.

[@ricdonato4328]

Oops, "...so your not cutting..." should be you are or you're. When spoken your and you're sound the same. However, when written your and you're have completely different meanings and usages. Hope that helps you.

[@simonandrews6160]

Great point about the stand up dimension. When working with a pattern rafter, always align with the top edge to achieve the best plane across common rafters. Birdsmouth depths will vary as the depth of each timber varies. Still and issue with today's timber, albeit to a lesser extent. The one third max rule ensures the strength of the eave overhang and has no impact on the strength of the rafter between plate and ridge. Nothing more satisfying than two rafters locked in at the top plates with birdsmouths, meeting the ridgeboard with perfect plumb cuts. Be a tradesman and cut a birdsmouth. Also, use trig to find your rafter lengths, none of this stepping off with a square, compounding error, or consulting apps and little red books. Or, god forbid, pulling a tape between the ridge and plate for each rafter, like a caveman. Old school chippies keep the faith. Birdsmouths forever. Love your work Buildsum Amen

[@Buildsum]

Hi Carl, thanks for your comment, I agree it is certainly very satisfying to calculate everything out and have it all fall perfectly into place on the roof. I don't think that Birdsmouths are going anywhere soon.

[@NovaAmbiance]

I am building a low pitched patio cover 1:12, in foregoing the birds mouth with Simpson strong tie connectors. After reading the comments in this I think with my low pitch I won’t have to worry about slippage… with my experience with many materials, I have convinced myself that a bird‘s mouth would also result in more possible noise in the later future, from additional wood on wood contact, If the thing can even budge after I’m done with it.

[@Buildsum]

Hi Mate, yeah I don't think you will have any issues with out the Birdsmouth. Thanks for your comment.

[@daveferranda9379]

Possibly implemented to allow for modern timber's smaller sizing and lower strength.

[@christerlundgren3805]

In Sweden its rare to do birds mouth, anchors screws or anchor nails on steelconnectors.. Boring I might add, thousands of screws on a house already. Now and then I get to do birdsmouth on a old house, and I like the simplicity and to smack in a few nails 😀. And the young lads in the trade don't know how to figure it out 😂. When I show how to mark it out with a speedsquare the always go: Ohh, so simple and quick. The tradeschools ain't back to date... Nailguns, etc is familiar to them... Well, ol grumpy viking has bitched enough now 😁

[@Buildsum]

Thanks, Mate, good to know, yeah it certainly is satisfying when that birdsmouth slides into place.

[@zefrum3]

Good argument for not doing the traditional thing as it actually weakens the rafter, its an extra step now and the framer still needs to use ties. A few comments below suggest birds mouth cuts are good b/c it straitens the top plate...that doesnt sound right. Ideally you want your sheathing on the wall before its lifted and then braced, which should be straight...but even w/o, properly bracing the wall and using the straightest boards will eliminate this risk

[@Buildsum]

Hi Mate, thanks for your comemnt, I agree the plates should be straight before you start putting up the rafters.

[@jimmykatsaounis5317]

Didn’t know I didn’t have to Makes sense with available ties Thanks for your video

[@Buildsum]

Thanks Jimmy, Glad to help.

[@nasifahmed6768]

Love your content, timber connector is definitely a better choice, I don't know why here in the US, we have been using birdsmouth. I know Simpson makes those rafter connectors. Ahmed from Fayetteville,Arkansas

[@Buildsum]

Hi Mate,Thanks for your comment

[@Xavyer13]

I thought it was structurally better to join the rafter thru a birdsmouth but it seems that the fasteners are quite solid as well 🤔

[@user-tq1sp5ly9l]

I find that in a skillion roof situation Such as a fly over roof for a deck etc... If you don't have a bird's mouth the forces of gravity want the rafters to slide down hill off the roof beams or frames. When you have bird's mouth on the rafters it seems to transfer the weight directly downwards and the rafters will sit there on their own.

[@Buildsum]

Hi Mate, thanks for your comment.

[@Brave_Little_Toaster]

I stumbled upon this video trying to research to build a shed. I need to look into my local codes, but I feel like it would be easier to mitre the studs on my lean to than do bird mouth cuts.

[@Buildsum]

Hi Mate, this might be an option if you are doing a lean to roof kzbin.info/www/bejne/fH-rqqimeK6Ejq8 kzbin.info/www/bejne/rnLYgpeHbJ2gqKs

[@collcolin]

The 1/3 depth of cut rule These days with rafter sizes being increased for insulation and ventilation are they not sized larger than the structural strength so therefore could you go more than the 1/3 cut out to achieve less stand up Maybe it would be good to know the actual structural size of rafter then you could keep to those boundaries Also bird’s mouth the ceiling rafter nailed against the rafter should be plentiful I always think But still do the BM

[@Buildsum]

Hi Mate, good point however this is getting outside the scope of the code and into Structural engineer territory. I tend to agree with your comment about the ceiling joists, as long as you have a joist against each rafter then that will certainly help transfer the loads down to the top plate. Thanks for your comment.

[@am7442]

yep, I never use to birdsmouth the rafters. Just measured the overhang of the truss tail, then marked that on the rafter, put a nail in to make it easier to know when putting in to position, skew nail then triple grip later with the rest of the tie down.

[@Buildsum]

Hi Mate, thanks for your comment, using the nail seems like a good idea. Did you ever have any issues with passing inspections? Where abouts were you building?

[@am7442]

@@Buildsum hi mate,no never had any issues. Was working in Brisbane, Ipswich and Gold Coast.

[@Buildsum]

Thanks Mate, good to know.

[@am7442]

@@Buildsum no worries 👍

[@j.r7872]

Excellent! Agreed! Ninja.

[@Buildsum]

Thanks Mate

[@thedreamstation]

What’s that plate you use when you don’t want to use a birds mouth? Do you have any links for home depot or Amazon to find??? Which do you recommend to use?thank you

[@Buildsum]

Hi Mate, I think you are thinking of a Ribbon Plate which is normally used when you are using trusses, however the need for a Birdsmouth is not reliant on the size of the plate.

[@murraymadness4674]

Our building code in usa/california requires the rafter has minimum 1.5in bearing onto the top plate, so just using the rafter tie bracket is not legal, and frankly that seems a very bad idea to have the rafter bear on just a tiny point. What I do at least on sheds is use the bracket and glue in the wedge. That wedge is exactly the same size as you cut off the end of the rafter at the peak to attach it to the ridge board!

[@Buildsum]

Thanks Mate, good to know.

[@OMMITRA]

Good idea. Nothing goes to waste! What type of bracket do you use? The three grip type shown in the video or the Simpson hurrican type?

[@Buildsum]

@@OMMITRA Hi Mate, the code shows the Trip-L- grip but as the Hurrican has a higher rating I don't see a problem using it

[@OMMITRA]

@@Buildsum Thanks Buddy!

[@Benzknees]

Here in the UK nearly all new roofs are built from factory made trussed rafters, so birdsmouths are a rarity.

[@Buildsum]

Hi Mate, yeah we have a lot of trusses over here as well however there are still a few roofs cut on site.

[@wheres_bears1378]

When cutting a birds mouth how do you account for roof height? Wouldn’t the depth of the birds mouth decrease the plan height?

[@Buildsum]

Hi Sam, yes it does however when we calculate the rise of the roof it is taken from the x-y line which is where the back of the Birdsmouth intersects with the top of the rafter. To get the actual height of the roof from the top plate you have to add the Stand Up distance to the rise. Hope this helps

[@wheres_bears1378]

@@Buildsum thanks very much

[@jack460able]

With a typical 22.5 pitch roof the stand up for a rafter is 65 mm (according to the 1/3 rule)therefore the strutting beam on large spanning room would be a lvl 365 deep it would not pass code which states D/3 or 100mm whichever is greater even without a birdsmouth it would not be enough what would be a solution for this to pass code cheers keep up the good content

[@Buildsum]

Hi Mate, you may have to look at using a Steel beam rather than LVL, is could actually be cheaper than LVL in the long run.

[@neila9251]

Deeper rafters with no birdsmouth?

[@donaloconnor3352]

What does D/3 mean?

[@tazzieastwood2147]

Hi mate. Have you done a video on how to read the span tables. If not it will be great help if you do one.

[@Buildsum]

Hi Mate, I have a whole playlist on it actually kzbin.info/www/bejne/aJTWq5Scaq6AadU Hope this helps. For a shorter version have a look at this one kzbin.info/www/bejne/d3yXlJyFnaxmeLM Hope this helps

[@funnybonez321]

Possible to make a video on how to do a birds mouth?

[@Buildsum]

Hi Mate, it is all part of the process of cutting a rafter which starts with making a Pattern Rafter. kzbin.info/www/bejne/l2G2hGuirNaZbck Hope this video helps.

[@ibrahime4925]

Do you have a video on how to actually cut out a birdsmouth?

[@Buildsum]

Hi Ibrahim, not on how to cut it just how to mark it out, sorry.

[@jakedorange8991]

Well looks like I won't be cutting birds mouth any more

[@Buildsum]

Hi Jake, you might have to educate your inspector or PCA about this as well.

[@jakedorange8991]

@@Buildsum yeah I was unaware that I didn't have to cut them where can I find this information to reference to for the builders that will Def disagree??? Cheers buildsum

[@Buildsum]

Hi Jake, it is in AS1684.2 Residential timber-framed construction, Chapter 7

[@jakedorange8991]

@@Buildsum excellent many thanks

[@nextofkinoffice4668]

If you hand cut a roof with birds mouth you don't need triple grips is my understanding

[@Buildsum]

Hi Mate, nowadays you pretty much need triple grips regardless of whether you have the birdsmouth or not, so why worry about the Birdsmouth?

[@scottrhodes7091]

I have done it both ways it works fine.

[@Buildsum]

Thats great to hear Scott. When you didn't use the birdsmouth did you get any questions from the PCA or Building Inspector?

[@scottrhodes7091]

@@Buildsum I used it on small sheds and they wouldn’t inspect those at the time. The sheds are over ten years old and have had no problems.