[skifire]

Hi everyone,

I'm in the planning stage for a porch roof and I've run into a problem. My 1950's roof was constructed in a way that I am not familiar with and I can't seem to think though the valley construction. On my house, the rafter tails do not extend past the block wall, instead the ceiling joist extend past the wall to create the over hang. This may have been normal construction but it's my first time dealing with this. Our house has an "old part" and a "new part" the new part of my home that's not currently being worked on has traditional trusses.

Here is the model I have created for planning purposes and although the rafter angle is slightly off, it is close enough to illustrate what is going on:

The roof I'm planning to build will be open but my first truss (that sits above the house wall) obviously needs to help form a valley so that I can close of the existing overhang and start my open/exposed over hang and rafter tails on the porch roof.

This is where I'm stuck:

I did extend the tail of my new truss down until it was even with the bottom of the existing overhang as a visual aid.

Here is the same picture with the open gable rafters, please ignore the size difference. I made a mistake when modeling them up. The new exposed rafters will be the same height as the truss at the end of the day.

If I need to bring the porch rafter tails down to meet the existing overhang, I think I can. Visually it can be made to look OK (at least in 3D land). But I still need to be able to close off the end of the existing over hang.

To make things slightly harder, my roof pitch seems to be a 4.5/12 -- I measured this in 3 different areas and while it some times measures up at 4.25/12, it's usually 4.5/12, which I find a little unusually but that's what the measurement says. So I'm trying to match that angle as best I can with the new roof.

All that to say, does anyone have some reference material or a YouTube video for making this kind of connection? Any help would be greatly appreciated. I can also share the model if that would be helpful.

Thank you,
Mark

 

[skifire]

It's not for the height.

At the front of the porch I was able to dig below the corners and underpin it with a proper footer (our frost line is 30"). I can't do that up against the house due to other sidewalks being in the way. So I opted to go above the wall since it's a continuous wall all the way to the basement footer, if got plenty of support from there. The main drawback being the extra height.

 

[skifire]

I'd definitely prefer to go that route. Unfortunately, I don't have framed interior walls, their are 2x4s pinned screwed to the inside of the block to act as a furring strip.

Based on your suggestion though, I think I need to reach out to our architect about cutting into the wall and setting it flush. Thank you for the advice!

 

[skifire]

First, thank you all very much! This is very helpful and I appreciate the constructive feedback -- pun intended.

I'm in the process of reworking the model based on some of this so it's definitely unfinished but I think I have a workable direction.

The porch is 12' deep and 20' wide and 4" thick at it's thinnest point. I've already underpinned the outside corners.

Based on the information learned here as well as talking to a few people locally for code, it seems that putting the beam in a pocket will be the better way to go here.

I will be required to fill the entire column with concrete and rebar, and have enough room for a 2 1/2" (minimum) concrete pad for the beam to rest on. I'm pretty good with concrete so that's a lot less intimidating that dealing with the beam on top of the wall.

The reason for the full truss in the back -- I want to continue my board and batten siding inside the porch so I'll need something to attach it to. The rest of the porch will be open frame.

I'll still need rafter ties to prevent them from pushing out on the beam but I don't foresee it being difficult to make those look nice.

All of this feedback has been great. I'll post the next version of the plan once I have the model ready.