Re roofing tricky lean-to with split level wall plate. Wall plate/header combo from 3x 4"x2" is ok?

[Safety First]

Hi and thanks for taking the time to look and hopefully advise...

Short form; see pics and Q: Will this 'beam'/wall plate/header/design for over the doorway aptly support the rafters, or is there a better way?


Longer version; We have a single skin brick lean-to with half pan tiles and half timber and glazed framework. I doubt the concrete base has DPM. The roof leaked a lot.

Inside is a larder, WC and porch with some much needed storage. Not heated. It will never be inhabited. Solely as before- thoroughfare, WC, and storage.

Hard to see from pics but the guttering had a 'z' joint in it to meet the two roof sections with same pitch but being diff lengths.

Overall roof approx 4.5m x 2.6m.

I want to remove the old rafters that held tiled section as well as the old framework and wall (RHS) that held glazing and replace with all new timbers up to and including re-roof. Single pitch, straight run of gutter. Probably clad on the right hand side with shiplap.

MS Paint sketches are pretty bad/not to scale but hopefully convey the situation and current plan.

Masonry wall (LHS) wall plate is 165mm lower than header of doorway. This header picks up rafters from skinny timbers that were glazed.

If I build up the wall to meet the door header height, I can then send across a wall plate that will carry the new rafters. Its a wall plate/beam combo that goes from masonry to timber.

Q: will my 'design' for this (OTT?) wall plate/beam work to support the rafters? It seems like a waste of timber to span this across the whole length with so much wood, but what are the alternatives?

I think a concrete lintel would want masonry support on both ends. The front right window is to be removed but I am not confident to lay blocks up to the required height to offer a support for a lintel and imagine a wall would need support from a perp wall meeting it. Stud work is within my abilities and the whole thingon the RHS will be shiplap clad anyway.

 

[cdbe]

Maybe ask for this to be removed to the building section. Your timber lintel seems adequate, only needed over the door and should be under the wall plate not on top, maybe double up the vertical stud on the right. Alternatively an angle iron under the wall plate would also do the job. I'm not sure you need to resin the wall plate to the masonry - generally it should be strapped to the masonry lower down to help resist wind uplift.

 

[Safety First]

Maybe ask for this to be removed to the building section. Your timber lintel seems adequate, only needed over the door and should be under the wall plate not on top, maybe double up the vertical stud on the right. Alternatively an angle iron under the wall plate would also do the job. I'm not sure you need to resin the wall plate to the masonry - generally it should be strapped to the masonry lower down to help resist wind uplift.

Many thanks- I will (try) to make a more succinct post on building section and link to this..

Re your point of timber lintel being needed only over the door-this would save timber lintel from being used across the whole of the masonry. I.e., meaning raise the LHS masonry, rather than extending the lintel to get the height? I guess I dont know the relative costs of bricks and mortar vs timber...