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Weep openings provide drainage in this brick wall (C) Daniel FriedmanFlood Damage Leaks at Veneer Wall Weep Holes
Masonry veneer wall flood damage, defects & inspections

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Flood water entry through weep holes in brick walls:

Area flooding sends water and mud through weep openings and into veneer wall cavities. What problems ensue and what should homeowners in areas subject to flooding do about venting brick veneer walls?

This article series explains the purpose of drainage openings & rain screens in solid brick walls and in some brick veneer walls: brick wall weep holes and recommends their use in new construction and in some brick wall repairs or retrofits.

Weep holes in building exterior masonry walls (brick or stone) are a drainage system that is used in cavity wall or rain-screen wall construction methods to get rid of water that has penetrated the outer wall skin or surface.



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Brick Veneer Wall Leakage Problems in Buildings Exposed to Flooding

Brick wall weep holes below grade (C) Carson Dunlop AssocCarson Dunlop Associate's sketch at left [Click to enlarge any image] illustrates an improper backfill that will certainly direct surface runoff or flood waters towards the building wall cavity, almost assuring water entry, rot, insect damage over time.

Carson Dunlop Associates, a Toronto home inspection, education & report-writing tool firm, notes in their educational mateiral that in-slope grade and burying veneer wall vents is improper.

But even when the lower edge of a veneer wall and its vents are a foot or more above ground level, area flooding is likely to cause water entry into the veneer wall cavity, leaving mud behind and risking clogging of the veneer wall vent system.

Even after flood-waters reside a blocked veneer wall vent system risks future damage to the building if water is trapped in the wall cavity.

Article Series Contents

Priorities for Minimizing Mold & Water Damage in Flooded Homes Wet Through Brick Wall Weep Holes

Question: is it really necessary to remove floor-wall trim in flooded Texas homes where water entered through brick weep openings?

2017/08/31 Sarah said:

@Rob, we have the same issue in Houston so I am anxious to here the responses.

No water in our house but some of the marble tiles at front of house showed darker along the grout lines extending out from the walls.

We have not done any moisture testing but our real estate neighbor has warned of dangers of mold so we don't want to ignore but are not sure what to do or how quickly we need to act.

2017/08/31 Rob said:

We had flood water get right to, and maybe an inch above the brick weep holes. In one location we had a small section of baseboard damage.

No other baseboard damage but we get a higher moisture reading in several other locations using a cheap 2 pin meter from the hardware store. Do we need to remove all of the baseboards, insulation, and sheetrock or will those dry out by themselves?

The water was at that level for several hours but less than a day. Most of the readings were in the green and less than 12% on the wood scale when checking the drywall right above the baseboard. Thanks for any help you can give.

Reply: remove wet trim and wet drywall, find extent of wet materials

Sarah and Rob,

Flood damage & mold prevention advice for Houston & other flood areas in Texas & Louisana: August - September 2017

I may be able to give better, and more economical advice when I know more details, have see photos, and have details of what you found when exploring for wet areas as I will describe, but here is what I recommend as some initial steps for homes that were NOT subject to deep flooding that sent water inches or higher into finished building interiors.

Basic concept: wet floor water weeps upwards

In my experience even a half-inch of water on floors that just wets baseboard trim will, especially if left for hours or days, seep upwards in the wall cavity, by capillary action, following wood and drywall higher in the wall cavity.

Basic Steps to Remove Wet Materials & Dry Out to Prevent Mold

IF water has wet floors in a building such that it went behind even just the bottom inch or so of floor-trim baseboards and drywall, wetting those spaces then you really want to take the following steps:

1. Remove floor trim baseboards in wet areas: AS SOON AS POSSIBLE pull off the floor trim baseboards, wipe them dry and place them in a dry location to finish drying. If you can work carefully (I use pairs of small flat prybars) to remove the trim it can usually be dried and re-used in the same rooms, saving time on buying, cutting, painting new trim boards.

2. Remove wet drywall up 12" or more: Cut off & remove the bottom 12" of drywall in any areas where the drywall was wet, even if only its bottom inch was wet. Remove any wet insulation, let the wall cavity dry.

3. Speed dry-out if possible: Fans and dehumidifiers can speed the drying process if you have safe electrical power. If we get these materials dry in 24-48 hours after soaking we can usually avoid a more serious mold cleanup job . A combination of fan to stir air circulation and a dehumidifier to remove moisture will help dry out a building interior much more quickly than either of those appliances will do on their own.

How Much Time Do I Have to Dry Things Out?

If you have already removed and tossed out wet wall-to-wall carpets and carpet padding and then do the tasks above, quickly enough then you can avoid a more costly mold problem.

Watch out: for "mold prevention" fraudsters: If you do not open wet wall bottom cavities, there is absolutely no magic system like "water extraction" by dehumidifiers alone, nor by blowing air through little holes cut along a wall that has ever worked successfully in my (more than 40) years of experience.

I have pulled off baseboard trim weeks after a room appeared "dry" to find that there was still visible water on the trim back side, and by then, a mold colony happily blooming away on both sides of the drywall low on the walls.

You don't have to do this aggressive dry-out treatment everywhere

If you can establish by observation or by measurement using a simple pin type moisture meter that water didn't go all the way around a room, just pull off the wet baseboards and open the wet areas.

Usually wet wood and drywall will peg the moisture meter over into the red area.

Moisture under 18% in wood is acceptable UNLESS you have reason to think the moisture meter can't see far enough into the wall - eg if you waited too long to make these measurements (days) and the outer surface is dry but back side of trim and hidden drywall behind the trim are actually still wet.

In that case explore the most-suspect area as I describe here.

Explore the Most-Suspect Flood Water-Damage Areas First

Go to the most-suspect-wet area, (look at water marks and debris), open that by pulling off trim and removing wet drywall, and keep going until you find dry baseboard and drywall and wall cavities. Stop there.

Check the back side or previously-hidden side of drywall and wood floor trim that you remove. If it's moldy more cleaning is needed. You don't need to "kill" mold. Simple cleaning wood with detergents or spray cleaners followed by drying is enough.

If drywall back side is moldy, cut more off up another foot or more as needed until you can see that the remaining drywall and any insulation in walls is dry.

What if the Building is Already Moldy

See MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD

Keep me posted. You can also send photos and details along with follow-up questions by email using our page top and bottom CONTACT links.

We provide pro-bono consulting to Texas, Louisiana & other flood victims by email.

See FLOOD DAMAGE REPAIR PRIORITIES where we issue safety warnings and provide links to articles discussing specific flood damage control, demolition, flood damage repair articles.

Watch out: for safety, before entering a building that has been flooded review BUILDING ENTRY for DAMAGE ASSESSMENT

Seal Up Weep Holes in Brick to Avoid Flood Damage?

Brick weep opening screens at the Van Scriver Elementary School, Haddonfield New Jersey (C) Daniel FriedmanReader Question: Should I seal weep openings in our Texas home exposed to flooding?

2016/03/25 S Schneider said:

We had severe flooding in a brick town home in Tyler Texas recently, for the third time. The contractor recommended sealing up the weep holed. He said that's where the water was flooding in.

We have French drains already. Reading your site, I'm concerned sealing the weeps is a bad idea?

Reply: Suggestions for reducing flood damage to wood-framed brick-veneer covered buildings in flood prone areas

SS

I agree that water entering a brick veneer wall in flood conditions is a serious concern. Brick veneer walls are built to shed water from wind-driven rain but not to resist standing floodwater. Floodwater will pass through the veneer and enter the wood framed wall cavity wetting insulation, drywall, and other components, inviting costly mold damage too.

Ultimately homes flooded in this manner need to gut the wall to framing, replacing insulation and drywall.

I would not normally advise sealing weep holes in a brick wall unless you are changing the wall structure, design, insulation and drainage system to a flood-resistant wall that prevents water entry in the first place. We describe that approach at BRICK VENEER WALL REPAIRS in FLOOD PRONE AREAS

Otherwise, while sealing vent or drain openings in a veneer wall might slow water and mud entry into the wall cavity during flooding, it will also trap more frequent wind-driven rainwater that will enter the wall and be unable to drain out.

The result will be a catastrophe: water trapped in the building wall and ensuing damage beyond mold to include rot and insect attack.

Let me offer more general comments, gripes, worries about building flood resistance: no normally-constructed home is built to work like a boat: that is, slab, foundation, and wall structures as well as roofs may be water-resistant but only roofs are water-proof and even roofs rely on shedding water to keep water out.

That is, except for membrane roofs, if a roof were under-water it would leak. Similarly, foundations and walls of most buildings cannot resist the forces of standing water against the building exterior and certainly that's also true for a building's exterior walls above-ground. Those walls are designed to shed water not to be waterproof if inundated.

And if we *did* build a building exterior that was totally waterproof we'd have moisture and mold problems indoors from interior generated water and moisture - those long hot showers and spaghetti cooking on the stove.

What all this means, I'm sorry to say, is that flood-proofing a home in an area that is frequently inundated, that is flood-proofing a home located where water frequently rises up along the exterior walls, will require raising the home above the flood level - on a higher pier or other foundation system - or moving.

Question: ground clearance height for brick veneer wall weep openings

2016/06/21 Shayne said:
What is the min distance a concrete path can be from the bottom of the weep hole

Reply:

Interesting question. I've not seen a ground-clearance specification for brick veneer weep holes. But you're quite right that water entering such openings from the ground could cause building damage.

Schneider's question and answer in the article above discusses Texas flood water entry into structures through wall weep openings.

A subtle component of just what that damage risk is depends on how the veneer wall is constructed, the height above grade of the bottom masonry lip or steel rail on which the veneer wall sits, and the in-wall height of the in-wall flashing at wall bottom that directs any in-wall-cavity water out through he weep holes.

My OPINION is that the weep hole should be high enough that it won't pick up surface water runoff during rain or periods of melting snow; that may vary by individual situation from an inch upwards.

Brick veneer wall stopgap & rebuild suggestions for homes located in areas of flooding

Stopgap measure to protect homes with brick veneer walls:

Sandbagging against weep holes around base of veneer wall: When you anticipate floodwaters around the home, dense packing of sandbags around the wall bottom can slow water penetration into the veneer wall cavity and should also reduce the volume of clogging mud that will enter those openings from flooding

The topic of repair and reconstruction options to reduce future flood damage to brick and brick veneer wall homes has moved to a new, expanded article now found at BRICK VENEER WALL REPAIRS in FLOOD PRONE AREAS. Please see that article for details and an ongoing discussion of flood damage repair and reconstruction for homes built with brick or brick veneer walls.

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Continue reading at BRICK VENEER WALL REPAIRS in FLOOD PRONE AREAS - repairs to reduce future flood damage, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see BRICK WALL DRAIN, FLASHING, VENT SOURCES

Or see FEMA CONTACT INFO & TELEPHONES

Or see FLOOD DAMAGE REPAIR PRIORITIES

Or see FLOOD DAMAGE CLEANUP & REPAIR GUIDE - home

Or see STUCCO WALL WEEP SCREED DRAINAGE

Or see this

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INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING STRUCTURES

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