Leakproof

This is a rewrite of an article from my newsletter of September 9, 2000

In 2000 I was at a newly constructed home to set a 90-day Radon test. I had inspected this home about a month earlier and was impressed by the visible quality, which was much improved over what I had witnessed in the past from this builder who is a major player in this market then and now.

One of the things noted in my inspection was that the copper front porch roof had not been flashed at the brick wall. Needless to say, this concerned me and was prominent in my report to the buyer. Upon my return visit, the owner ask if I would look at some problems they were experiencing. They expressed concern that they were having difficulty getting the builder to respond to their concerns. Walking through the home I was shown water stains on the drywall below the living room, den and master bedroom windows. There were also water stains on the windows. Should water stains at windows be acceptable in a newly constructed home? I don't think so. So what was going on here?

Before I share my insight on this issue, let me carefully tell a story from my distant past when I was commercial building contractor.

It was pouring down rain as my phone rang. On the other end was a very prominent local architect. “Chris, could you please come to my office? I have a problem and would appreciate you taking a look while it is raining. Water is pouring into my office.”

I had not constructed this building (thank God) which was not very old, but had been designed by the person callings firm. Arriving at the site, my first observation was that the masonry details at the windows were complex making them difficult to effectively flash inside of the wall. Walking into the office in question, even I was shocked by what I saw. It was still pouring down rain outside, and the wall was not just wet or dripping, water was pouring through the wall similar to water pouring out of a bathtub faucet. The architect, supposedly a recognized expert on such issues wasn't just upset, he was mad, cursing the contractor, as he attempted to protect his furniture, equipment, books and documents.

My immediate conclusion?

Overly complex masonry details in association with inadequate through wall flashing. We were employed to check out the total building, which was no small undertaking. The conclusion, this one office wasn't the only issue; this same issue was duplicated throughout the building at most wall openings and roof to wall connections. At some point soon, water may be pouring in all over the building. Overly complex design details associated with poorly managed and inadequate installation of the flashing was clearly causing this problem at most locations. You don't even want to hear the cost associated with properly fixing something like this on a major commercial building. Since that time I have unfortunately had to address this issue on numerous commercial as well as residential structures. I have witnessed deals in the tens of millions fall apart because of this issue!

Flashing is an often-ignored, overlooked and unseen major concern in the construction process. Wouldn’t you love to purchase, or as a Realtor sell, a newly constructed home, or even an existing home and the roof and/or walls leak thirty days after the buyer's occupancy?

Back to our original story on the home with the water stains. Remember, the home inspector does not have x-ray vision and can't see inside of the walls, he must see the results of the problem and conjecture, based on his knowledge and experience, as to what is going on. There had been recent, heavy wind blown rain. My conclusion was the same as the past commercial building. There is inadequate and/or improperly installed flashing at the sills and heads of the windows.

Since this was a brick veneer home, the only proper permanent fix involves removing the brick window sills and the brick above the header (top) support angle, installing proper flashing with end dams and replacing the brick. Doesn't sound like much fun, does it? You can believe this is very complex, expensive and messy. Temporary and questionable fix, waterproof the brick. Had this been any other type of siding, the issue is similar as is the fix. The siding must usually be removed, and often the windows to permanently repair the problem.

What makes this even more interesting is that this builder has a reputation for detesting private home inspectors and often commenting: "This home meets code, and I don't have to do anything he says!"

Did this or most homes meet code? Let's look into the code in force at the time and see. What flashings are required? The quotations are direct quotes from the code (in 2000). Take the time to read this, you may learn a lot!

"703.3…Horizontal joints in panel siding shall be lapped a minimum of 1 inch or shall be flashed with Z-flashing."

"703.7 Masonry veneer, general…Flashing shall be installed over steel angle and a minimum of 6 inches under the wall sheathing."

"703.7.3 Flashing. Flashing shall be located beneath the first course of masonry above the finished ground level above the foundation wall or slab, and at other points of support, including structural floors, shelf angles and lintels when masonry veneers are designed in accordance with Section 703.7. See section 703.8 for additional requirements."

"703.8 Flashing. Approved corrosion - resistive flashing shall be provided at top and sides of all exterior window and door openings at top and sides of all exterior window and door openings in such a manner as to be leakproof, except that self- flashing windows having continuous lap of not less than 1-1/8 inches over the sheathing material around the perimeter of the opening, including corners, do not require additional flashing; jamb flashing may also be omitted when specifically approved by the building official. Similar flashings shall be installed at the intersection of chimneys or other masonry construction with frame or stucco walls, with projecting lips on both sides under stucco copings; under and at the ends of masonry, wood or metal copings and sills; continuously above all projecting wood trim; where exterior porches, decks or stairs attach to a wall or floor assembly of wood-frame construction; at wall and roof intersections."

Proper "step-flashing" 

"903.6 Side wall flashing. Flashing against a vertical sidewall shall be by the step-flashing method."

"903.7 Other flashing. Flashings against vertical front wall, as well as soil stack, vent pipe and chimney flashing, shall be applied according to asphalt shingle manufacturer's printed instructions.

"REROOFING…910.5 Flashing. Flashing shall be reconstructed in accordance with approved manufacturer's instructions.

There is one key word in all of this, "leakproof". If it leaks, it does not meet code! All of the rest is just how to make it leakproof. That being said let me share with you some things that I see which don't meet code and/or are not "leakproof". These issues are by no means limited to the problem builders, they are everywhere, even on the best builder’s homes.

1. The code calls for flashing over steel lintels to be installed "6 inches under the wall sheathing." I have hardly ever seen this done. This is often the problem with water leaking at window headers.
   
2. There are some issues with installation of self-flashing windows and house wrap. To be "leakproof" the house wrap should be lapped over, not under the flanges on the top and sides of the windows, and under the flange at the bottom. Do it differently and water will get behind the house wrap and into the wall.
   
3. "Self-flashing" windows used in masonry walls confuse most builders. Just because the window is self flashing does not eliminate the requirement for support angle and brick sill flashing.
   
4. For a brick sill flashing to be "leakproof" the flashing must extend below the sill on a wood window and below the bottom flange of a "self-flashing" window.
   
5. 
   In order for a window sill or support angle to be "leakproof" it must have "end dams". This is referred to in 703.8 with the words "at the ends of" but is not very clear. I have never seen an end dam used in residential construction and very rarely and only recently in commercial construction. To have an "end dam" the flashing must be shaped and turned up on the end in such a fashion to prevent water from leaking over the ends of the flashing. This is also recommended to be installed at the end of all flashing applications such as at the top of openings or anywhere where water could leak over the end of the flashing.

This is NOT flashing!

For those of you who get upset when home inspectors write up existing homes for improper or lack of roof flashing, pay close attention to 910.5 above. When homes are re-roofed, they fall under the current code and must be flashed. Roofing mastic, irrelevant how thick or beautifully applied is not flashing! It will in a short time crack out and leak.

How does all of this apply to existing homes? Remember, home inspections are not code inspections. I guess it all depends on your client. Most clients desire a "leakproof" home, don't you think? The issue is not does it meet code, but will it leak and what repairs will be required to prevent it from leaking.

I could go on and on about this subject. I could talk about the fact that roof flashing at masonry roof to wall connections should extend through the wall, not be applied to the outside. I see this on some older homes, but never on new construction. Flashing must be "leakproof". Flashing applied to the outside of a masonry wall will never be leakproof. Water goes into and through brick and block walls and must be directed back to the outside by through-wall flashing. There are many other issues related to flashing which we will not spend time dealing with here.

The main issue is, builders need to educate themselves and their subcontractors on proper flashing applications, insist that their homes be flashed properly (be made "leakproof"), rethink their priorities, and supervise their flashing installations. Quality construction is much more than what you see on the outside. Just because it looks good, doesn't necessarily mean it is good.

The miracle is that we don't see more leaks than we do. It's definitely not because builders build quality homes to code. They don't leak in spite of our (please note the use of the word our!) poor construction practices.