CRACKS! Switching from wood shakes to concrete tile

[Kenton H. Shepard, CMI]

This home was built on expansive soil, but (according to the plans the original owner showed me) foundation design included concrete caissons (underground columns) which rested on bedrock and the poured concrete foundation walls had 4" cardboard void forms beneath them to structurally isolate them from soil. This drastically reduced the chances of cracks resulting from heaving of expansive soils.

The owner did say that after a severe hail storm damaged the original wood shakes (2-3 lb. per sq.ft.), they were replaced with concrete tile (13 lb. per sq.ft.).

[Russel Ray]

Originally Posted by kshepard

This home was built on expansive soil, but (according to the plans the original owner showed me) foundation design included concrete caissons (underground columns) which rested on bedrock and the poured concrete foundation walls had 4" cardboard void forms beneath them to structurally isolate them from soil. This drastically reduced the chances of cracks resulting from heaving of expansive soils.

The owner did say that after a severe hail storm damaged the original wood shakes (2-3 lb. per sq.ft.), they were replaced with concrete tile (13 lb. per sq.ft.).

All of those cracks would cause me to pause. There is compression going on, as indicated in the first picture, which could definitely be caused by a heavier roof. If you get in the attic, or if there's an unfinished garage, you should be able to see additional structural framing to distribute the heavier weight of the roof more evenly around the structure. If you don't see that, you definitely have a compression issue. If you do see it, then you don't really know when the cracks occurred because they could have occurred first with the roofing company coming back to put in the additional framing once the cracks occured. However, with what you've provide in your post, I'd definitely have the oldest and most experienced roofing contractor look at it first. He will be less expensive than the structural engineer and will be familiar with compression issues from heavier roofs than what the structure was designed for, as well as ways to repair or prevent further damage.

Here's what I think. The roof is falling/sagging in the middle, resulting in compression in some interior middle places, which I think picture 1 is, somewhere interior middle.

As the roof sags in the middle, it's pulling up on the perimeter areas, resulting in tension cracks, which is what I think pictures 2 and 5 are. Pictures 3 and 4 could go either way. I think there's some compression at the right in picture 3, where there's a small U-shaped crack and what looks like a hole.

Did you walk across the street or in neighborhood places to see if the roof is sagging in any areas? That's a big part of my roof inspection.

I won't say what picture 4 looks like, but it reminds me of an episode of "Everybody Loves Raymond."

[Jeffrey R. Pope]

Even without seeing the cracks, here is my standard. . .

Concrete tile has been installed on a roof framing system which was originally designed to carry asphalt composition shingle, or some other relatively light-weight material. You should request documentation that will verify that the roof and structure have been approved or reinforced to carry the weight of concrete tiles, which are substantially heavier than most other types of roofing material.

[Kenton H. Shepard, CMI]

I was asked by the original homeowner to look at the home, which is not for sale, because he was concerned by by the cracks and some sagging floor framing not related to these pictures.
The first thing I asked was if he'd had a structural engineer approve the roof framing for the heavier roofing material. He said that it had been approved for the heavier material with no need for additional suppports at the existing trusses. Nothing had been done to them.

Cracks began appearing after the roof change, and no additional cracking has taken place over the past several years.

[Russel Ray]

Originally Posted by kshepard

I was asked by the original homeowner to look at the home, which is not for sale, because he was concerned by by the cracks and some sagging floor framing not related to these pictures.
The first thing I asked was if he'd had a structural engineer approve the roof framing for the heavier roofing material. He said that it had been approved for the heavier material with no need for additional suppports at the existing trusses. Nothing had been done to them.

Cracks began appearing after the roof change, and no additional cracking has taken place over the past several years.

Sounds like the structural engineer missed one. Since there has been no additional cracking over the past several years, it sounds like the roof has now settled and one should be able to patch and paint the affected areas.