Thursday, September 6, 2018

Construction - Porch , Solar Overhang, Soffets and More

My blog posts over the past several months have had more to do with dirt work than with carpentry.  While there is still some dirt work to do, mainly installation of the insulation/watershed umbrella west of the house, it is good to get in some carpentry for a change.

Framing for the Screened Porch
Glen, a journeyman carpenter friend, and I took advantage of some warm and dry weather in January to do most of the framing for the porch
Framing for the hip-roofed screen porch
but we were not able to carry it to the sheathing stage until mid-summer because of rainy spring weather and the fact that I needed time off from carpentry to finish the dirt work that I described in recent posts. The hip roof for the porch was well beyond my expertise so it made sense to stand aside and let Glen lead rather than learning its complicated construction for a one-time situation.  In order to save money and to be able to design as we worked, we stick-built it in lieu of trusses.  The framing included ceilings for both the porch and the walk overhang to make them cooler and have a more finished look.


Covered Walkway
We framed and sheathed a roof for the walkway that runs between the porch and the front door of the house.  Since it even extends slightly over the nearest garage door, we will be able to navigate undercover from the kitchen/porch door to the front entry or garage door.  The walk overhang is a continuation of, and blends in with,
This photo shows partial framing and sheathing of the
overhang for the second story clerestory windows as well
as the covering for the walkway between the screened
porch and the front entry; also visible is the beginnings
 of the temporary second story scaffolding against the
south wall

the porch roof.  It is carried by a double 2 x 12 beam running from the porch to the house without intervening post support.  Since the overhang is wider than the walk, a post would have required unwanted penetrations through the insulation/watershed umbrella (the installation of which was covered in a prior post).


Clerestory Window Overhang
All that is needed to keep unwanted midsummer sunshine off of the second story clerestory windows an dedicated overhang extending about two feet outward from the house just above the top trim for the windows.  Here pre-made trusses did make sense for saving time and money.  Closed cornices at each end of the overhang handle the transitions between the facia of the steeply sloped overhang and the facia of the low-slope second story roof.  The one at the west end could be built from a ladder standing on the first story roof but the one on the east was 25 ft above the ground and its complexity would require an impossible number of trips up and down a ladder. 

Po Man's "Cherry Picker"
Second stage scaffold
Construction of the east end of the overhang was a perfect example of the extraordinary measures one uses when working alone with a tight budget.  A contractor would probably have called in cherry-picker-like equipment for the job or set up steel scaffolding whereas I knew that working alone would take sufficient time to make rental fees for either approach off budget.  I constructed instead a substantial temporary scaffold from which to work safely.

The scaffold, that was anchored to the floor and ceiling inside the house and cantilevered through the wall, was done in two stages.  The first was adjacent to the south-facing wall for the purpose of framing, sheathing and roofing
Anchoring design for the cantilevered scaffold

the overhang as well as installing the facia and soffet.  The second stage was added later at a right angle to the first and wrapped around the corner of the house for the sole purpose of building and painting the closed cornice at the junction of the overhang roof and the second story rake roof and the associated soffets. The second scaffold, though, was in the way of installing the garage roof so it gave way to a successor that I will describe in a future post.  The south scaffold stayed in place until the metal roof and the soffet for the overhang were completed but will be in the way and have to be removed before installing the first story metal roof, the clerestory windows and the second story metal siding.

Soffet / Cornice Construction
The framing for the underside of any roof overhang comprises either rafter tails on the eave side or their equivalent called lookouts, on the rake side.  The tails and lookouts can be left exposed for a rustic look or can be veneered on the
Wedges added to the rafter tails (green);
notice the use of the Rainhandler instead
of a conventional gutter
bottom with a soffet, which means that, on the rake side, the soffet follows the slope of the roofin one direction and is horizontal in the other while, on the eave side, the soffet simply follows the slope of the roof.  The transition of the facia at the corner between the eave and the rake is uncomplicated whether there is a soffet or not.


However, the eave side is often modified to give a more finished look by making the soffet horizontal with special framing or by using
proprietary soffet materials like vinyl or metal to effect horizontal-ness without the benefit of framing.  But doing so creates an awkward transition of the facia and the soffet at the corner between the eave and rake that has to be reconciled by what is called a cornice return.

Our design called for a horizontal soffets and cornice returns for all overhangs.  Since the pitch for all of our roofs is low, it was easier to add 2-by wedges, to the bottom of the rafter tails than to frame horizontally or use proprietary materials.  The cornice returns were relatively simple except for the abrupt change from the second story overhang and the low-pitch second story roof.
Using a jig on the table saw for cutting the wedges

Steel Soffets
Modern soffets are usually not framed in.  Instead they are created with short pieces of vented vinyl or aluminum, and occasionally steel, running perpendicular to the wall of the house.  I opted for steel soffet material that can be purchased in convenient 12' lengths that run parallel to the wall.  The way I used them was to frame (as in picture frame, not structural frame) the periphery of the soffet with salvaged 1x lumber that I rabbeted underneath to accept and hide the edges of the vented steel panels.  Once the panels were tucked under the frame, I screwed them to the bottom of the wedge-added rafters and the rafter tails.

Metal Roofing and Siding At Last!
The roof sheathing has been protected by either 6 mil plastic sheeting or 30 lb felt paper, or both, for many months while awaiting the day the steel roofing could be installed (prior post on temporary protection).  Finally, the completion of the porch and the overhangs made it possible to measure and order both the roofing and the steel siding.  (For a discussion of and the rationale for standing seam steel roofing, go to the post on roof design and for steel siding, go to the post on wall cladding.)

All that was needed for estimates on roofing and siding was to produce homemade scaled drawings that provided the information the manufacturer needed for both the steel panels and associated steel trim pieces. The manufacturer countered with two things:  (a) a list of components for careful vetting and (b) digital drawings that could be taken back to the building for dimension verification before finalizing the order.  In order to reduce the cooling load, we ordered roofing and siding with color shades that had a high solar reflectance -- light gray for the roof and white for the siding.

The next task is to get the garage undercover in order to have dry storage for the steel cladding.

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As a do-it-selfer-in-training, I welcome your comments.