Portland Surveys

PORTLAND SURVEYS

Site Survey

1 | QUALIFYING THE STRUCTURE

PREREQUISITES

Portland, OR is notorious for their rigorous structural requirements that will need to be met before they will issue a permit for the PV install. For that reason, its important to take care of a few preliminary steps before getting too far into the survey process:

Check the AHJ Registry to make sure you're actually in the city of Portland.
Look out for bonus rooms in the attic.
Look out for hips and valleys on conventionally framed homes.
Figure out early on if the roof is framed using prefabricated trusses, as this will save you a lot of time!

AHJ REGISTRY

The first thing you should do when you have a Portland project is to confirm that the project is in fact in the City of Portland AHJ. This is important because it is possible to have an address list the city of Portland when it is actually governed by another nearby city/township, like Gresham; it is worth noting that vice versa also applies. If your project is in Portland or in a town adjacent to Portland, you need to use the AHJ registry to check what the governing jurisdiction is.

Be aware that Multnomah County is annexed to the City of Portland for permitting purposes, so the same rules and standards apply when the AHJ pulls up as Multnomah County.

It is recommended that you create your own account using your ION email. URL here.

Once logged in, simply use the search bar in the upper left and plug in the address for the project.

We want to use the smallest boundary that populates as our AHJ. Typically, it will telescope in from State -> County -> City or township.

This is an example of a project with a Portland address that is actually in Gresham.

When this is the case, we know we can disregard the Portland requirements listed below and complete just a typical survey.

DISQUALIFICATION - CONVENTIONALLY FRAMED BONUS ROOM

Any conventionally framed roof sections where there is living space in the attic will be disqualified.

This is what this would look like from the inside.

You can also often visualize this from the exterior of the home:

When you see windows suggesting an upper level living space directly under a sloped roof like this, this is most likely what the framing will look like for that room in the attic space.

This section of the roof will be disqualified in Portland.

This dormer is connected to the same attic space. Most likely, it is fully vaulted.

This section of the roof will be disqualified in Portland.

On the other side of the home, we can see another bonus room framed into the attic.

We can conclude that this whole roof would be disqualified in Portland and we should end the survey at this point.

HIPS & VALLEYS

Along with bonus style framing, Portland has restrictions on roof hips/valleys.

Essentially, the panels can only be placed on sections of roof where the rafters run continuously from the ridge down to the eave.
This applies to roofs consisting of conventional framing.

Based on this; would this layout be approved by portland?

Would this layout work for Portland?

Maybe?

The graphic to the right shows the roof from the previous examples with each supporting rafter drawn out.

The red rafters are rafters that cannot be installed over
- Notice the restrictions apply to rafters on either side of the ridge.
- This is causing some of our modules to be placed over areas that are disqualified.
The dormer on the back of the home is an overbuild section, meaning that the rafters underneath are not interrupted by this structure like with typical hip/valleys,

If the dormer was not overbuild, then the mounting area could be restricted even further.

Now most of the modules are placed in areas that would be disqualified.

This is because a valley would be formed where the main roof joins the dormer which would mean that all rafters under that dormer end at the valley rather than extending to the eave.

TRUSS ROOFS

Let's review; what is prefabricated wood truss framing?

When you see prefabricated trusses, it's good news for the design. This is the easiest framing type to engineer on. Look for a series of triangular shapes with webbed supports and metal gusset plates fastening members together.

This type of framing is most common in construction from the 1970s onwards. If a home was built before the 1970s, it is a lot less likely to be truss framing but not impossible.

Quick facts about truss framing:

Pre-engineered and manufactured specifically for local structural considerations.
Consist of top chords, bottom chord, web members all connected using gusset plates.
Easier to Engineer PV on.

The image to the right shows the same structure as if it were a truss roof.

Trusses are pre-engineered and manufactured to local structural requirements before they are assembled on site.
For this reason, roofs using truss framing do not have the same restrictions on hips/valleys as conventional framing does.

This includes not just hips and valleys, but also attic living spaces, also known as bonus rooms. The example to the right is a diagram showing what bonus room framing looks like using prefabricated trusses.

If the framing is trusses, there are no structural restrictions and we may move forward with the project like normal.

Bonus style attic using prefabricated trusses. We are good to continue with the project!

Bonus style attic using conventional framing. These roof sections are disqualified!

A roof with hips and valleys using prefabricated truss framing. We are good to continue with the project with no restrictions on roof area!

A roof with hips and valleys using conventional framing. All roof areas with rafters attaching to hip/valleys will be disqualified!

2 | MEASUREMENTS

OVERVIEW

When the AHJ is Portland, Oregon, there will be several additional measurements we will need due to their strict structural requirements:

The horizontal distance from eave to the nearest structural support (knee wall or purlin/strut)
Photos of where load bearing walls are in relation to these supports.
The full span from the eave to the ridge beam measured along the ceiling joist.
The length of any collar tie.
Size of ceiling joist
Spacing of ceiling joist

KNEE-WALLS/PURLIN & STRUT SUPPORTS

For this, we will measure along one of the ceiling joists.

Measure from the very furthest joint nearest to the eave in the attic over to the location of the knee-wall/strut.
Indicate this meausrement on the side view drawing.

FULL SPAN

The full span will be from the eave all the way to the ridge measured along the ceiling joist.

Make sure to mark this measurement on your side view drawing.

Remember that span is the horizontal measurement along the ceiling joist, not the diagonal along the rafter.

Example 1:

Example 2:

COLLAR TIES

measure the full horizontal length of any collar tie as highlighted by the green bracket.

Make sure to add this on your sideview as well as applicable.

CEILING JOIST

Ceiling Joists, also sometimes called Floor Joists, are the members at the bottom of the attic space running parallel with the rafters.

Often, the size and spacing of ceiling joists can vary wildly from the size and spacing of the rafters.

Most often the ceiling joists are larger members.
Most often they are spaced closer together.

The example to the right shows what these measurements should look like.

SIDE VIEW DRAWING

This is an example of what your side view sketch could look like:

notice the consistent load bearing wall location between the side view drawing and the top view sketch.

More details about side view and load bearing wall sketches and how to complete them will be included later on in this training unit below.

2 | LOAD BEARING WALL & SIDE VIEW SKETCHES

RENDERING THE LOAD BEARING WALL DRAWING

gather all of your exterior measurements of the home in order to draw the perimeter of the home and exterior load bearing walls:
- Make sure to use some type of reference scale and make a legend at the top.
when drawing walls, remember that most walls are framed in with 2x4s.
- If your scale is 1 grid block equals 1 foot, make a consistent judgement about how to draw the walls.
- In this example, the surveyor has chosen to round up the thickness of the wall to 1' but will indicate the correct measurements of the interior dimensions.
This surveyor has started the drawing by doing a simple outline of the perimeter and representing the basic dimensions of each roof section.

This surveyor has started the drawing by doing a simple outline of the perimeter and representing the basic dimensions of each roof section.

Next, the surveyor will draw the exterior walls.
- Remember, this surveyor has chosen to represent the walls using a unit of 1 block thickness, so they will need to be careful to indicate the correct dimensions when labeling.

Now the surveyor will draw the interior walls.

The final step is to show the rafter direction.
- This surveyor initially did the whole drawing using the same color but came back with a red pen after the fact to help differentiate the rafters from the walls.

This process needs to be repeated for every floor of the home. The example above is a single story home but your project may have more than one floor.

3 | PORTLAND SIDE VIEW SKETCH

WHAT WE NEED

For Portland Structural requirements, it is important for surveyors to map out the following:

Structural supports in the attic such as knee walls and collar ties.
Obstructions in the attic such as HVAC, skylights, chimneys or other large obstructions that would limit access to the roof rafters.
Load bearing walls/common walls of the home.

To the right is the basic template you can use for most gable roofs in Portland. Note that if the roof is not a gable roof or has more complexity, you may need to complete a separate drawing on grid paper to show this.

DRAWING SUPPORTS AND LOAD BEARING WALLS

This is an example of how to utilize this generic drawing to show the information needed for a load bearing wall sketch:

This drawing shows what supports are present in the attic space.
This drawing shows that the knee walls are not landing directly on top load bearing walls.
The load bearing wall shown here corresponds between the top view sketch and the side view.

SHOW MEASUREMENTS

In addition, it is important to notate accurate measurements for:

Side view:

Total rafter span
Distance from the exterior load bearing wall to any attic knee wall or kicker support.
Distance between knee walls

Top View:

Distance from one exterior load bearing wall to the opposite exterior load bearing wall.
Distance from the exterior load bearing walls to any interior load bearing wall.
Distance between each interior load bearing wall.

REPRESENTING OBSTRUCTIONS

Obstructions can cause issues when structural upgrades are needed.

In the example on the right, the HVAC is restriction access to the rafters as well as the ceiling joists underneath.
We would be unable to perform a structural upgrade or install in this case.

USE THIS TEMPLATE

Print this document as needed to use as a template for drawings in Portland.

For item 3, it would be most appropriate to include the attic obstruction location on the load bearing wall sketch, both made on graph paper.
- 2 total drawings are needed.

Load Bearing Wall Sketch V1.pdf

4 | PORTLAND UPGRADES

OVERVIEW

Portland, OR is notorious for their rigorous structural requirements that will need to be met before they will issue a permit for the PV install. For truss roofs, there are not special considerations and they should pass with Portland no problem. The main issue is conventional framing; it is very common for conventional framing in Portland to require structural upgrades in order to meet Portland's structural standards:

Getting good measurements to begin with can help reduce the overall resurveys that will be needed.
Just remember, that even when we get great measurements, there is a higher than normal probability of returning to complete a resurvey to determine if a structural upgrade is possible.

Here's a step by step of how this will be determined:

The initial survey is completed wherein, the surveyor gets detailed structural measurements and completes simple side view and load bearing wall sketches.
Structural engineering will review these measurements and complete all needed structural calculations to either conclude that upgrades will be needed, or that the project will be structurally approved by the city of Portland.
If a structural upgrade is needed, the engineer will provide specific lumber sizes that will need to be able to fit in the attic.

This is an example where the opening to the attic will not allow us to bring boards into the attic.

This is the same example viewed inside the attic. As you can see, between the abnormally small attic access and the limited space in the attic, there is no wiggle room to get adequately sized lumber into the attic for potential upgrades.

In this example, we will have a look at the before and after of a structural upgrade to demonstrate the extent of upgrades that could be needed on any given project.

As you can see, there's considerable space in the attic for lumber as long as the attic access is large enough.

Note, the existing Knee Wall. Make sure to fully document this for structural engineering.
Also be sure to notate any piping or other attic obstructions that might hinder access to rafters that need to be upgraded.
- Most pipes are okay and shouldn't cause an issue, mainly it is mechanical units like HVAC and associated ducts that will restrict access to joists and rafters that would be a case for concern.

Here we see there appears to be a mechanical unit on the other end of the attic, likely an HVAC unit.
Make sure to always document locations for mechanical equipment as these areas of the attic are likely to be structurally disqualified since the HVAC unit would obstruct access to rafters and ceiling joists.

This is what the final upgraded attic space looks like for the survey above.

Notice that the engineer called to upgrade the collar ties, ceiling joists and also called to have rafters sistered.

Look how much space is occupied by the new lumber in the attic. That is why it is so important to get all the masurements and ensure that the boards will fit in the attic.

5 | quiz

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