Tag Archives: soffit panels

See the Pretty External Wall Girts?

See the Pretty External Wall Girts?

Readers of my latest two episodes are probably beginning to feel familiar with this commercial post frame building. As well as its challenges.

I will first point out something in this photo I find to be odd, although not (surprisingly) necessarily a structural deficiency.

Outside board on this building’s roof eave line is known as a fascia or edge purlin. A fascia purlin is defined (in ANSI/ASABE S618 “Post Frame Building System Nomenclature”) as, “a purlin that helps form the fascia of a building”. An edge purlin is, “A purlin in the most outer row of purlins. All fascia purlins are edge purlins but not all edge purlins are fascia purlins.” Looking at this fascia purlin, note there is a dark portion roughly 4-1/2 inches in width aligned with each wall column. These are truss ‘tail’ ends. This builder installed fascia purlins between truss tails, rather than across them as indicated on engineer sealed plans and our Construction Manual.

Effectively this should have made precut soffit panels all 1-1/2 inches too long, leading me to believe it is possible this building is three inches narrower than planned!

How fascia purlins are attached is yet another issue, as through nailing into truss tail ends was specified.

Now onto what is really an issue, not structurally, but from a functional standpoint. This commercial building’s owner is planning upon climate controlling it. As part of being able to effectively insulate walls, materials for commercial bookshelf girts were provided (as well as specified on plans by the engineer).

For extended reading on commercial bookshelf girts, please see https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/.

As we have seen from previous articles, this particular builder was not too savvy when it came to looking at plans. I suspect they are neatly tucked away behind a rear seat in his crew cab pickup.

The Straight and Narrow of Fascia: Hansen Building Disaster Part III

The Straight and Narrow of Fascia:  Building Disaster Part III

Look at the board on the far right. The one which resembles the coastline of New Jersey. It is what is known as a fascia board and it is pretty important it be straight.


Because not only do vinyl soffit panels attach to the underside of it, but steel trim covers the face of it. Steel trims are very happy to be installed on straight boards.

But other worries are looming in this photo.

The roof trusses were manufactured in a plant which seemingly has some challenges with plumb cutting (which was specified on our order) Read about plumb cutting here: https://www.hansenpolebuildings.com/2015/09/trusses-9/. None-the-less the builder might have stumbled upon reading in the plans or the Hansen Pole Buildings’ Construction Manual and seen the necessity to have cut the tails plumb. He instead has opted to just nail the fascia board onto the ends of the square cut tails.

This creates more problems – such as the inability to install the soffit panels. Which, since he left the framing off the sidewall to support the soffit panels, might have been why he quit where he did.

Notice, if you will, how the outside face of the bookshelf wall girts and the wall columns are in the same plane.

They are not supposed to be. The wall girts should extend outside of the columns by 1-1/2 inches. This allows for the outside of them to be flush with things such as the skirt boards, which the builder has installed on the face of the columns! I suppose the thought was the wall steel would just curve to make up the difference?

Tomorrow, the client proposes some solutions to some of the issues and I will give my take on why those solutions may, or may not work.

No Not F Channel

Hansen Pole Buildings Designer Rick recently asked me this question about overhangs and F Channel:

A question came up about soffit support. 

The client is a builder trying to close a garage for his client.  He asked about soffit/enclosed overhangs. 

He asked why we do not use an F channel trim to hold the soffit in place on the wall side instead of wood frame soffit support, commenting that the F channel is less time consuming and more material efficient.”

F ChannelIn typical stud wall construction, vinyl (aluminum or steel) soffit panels are typically held in place against the wall, by means of nailing a piece of trim known as “F and J’ to the wall of the building. This piece of trim has two “receiving” points, one horizontal to accept the soffit panels and the other below and vertical to accept the siding.

This makes for quick installation for the installer, as no fasteners are needed to be placed into the edge of the soffit panels, against the wall of the building – the F channel trim is relied upon to hold the soffit in place.

A stud wall is going to obviously be fairly rigid in the horizontal direction. All of those studs (whether 16 or 24 inches on center) are not going to bend.

In post frame (pole building) construction, regardless of how close together the columns are spaced, there is going to be a fair distance between them. There are numerous suppliers and builders who ignore this, and will place a single (usually 2×4) framing member flat on the outside of the columns.  They try to get by with attaching F and J trim against it, just like they would in stick frame (stud wall) applications.

The downside of this application is the single framing member is going to have a fairly large amount of flex. In an extreme wind situation, the member could easily flex far enough to allow the soffit panels in the middle of the span to fall out of the receiving end of the trim. Not good.

From years of experience (and finding out the hard way what doesn’t work), we came up with a solution which has eliminated the deflection issues. Against the pole building columns, we place two 2x4s nailed together to form an “L”.

This L, keeps the edge of the soffit closest to the building wall from being able to flex either up and down, or in and out. It provides a solid anchorage point – keeping the soffit panels where they belong, securely attached in place.