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PORCH CONSTRUCTION & SCREENING
RETAINING WALL DESIGNS, TYPES, DAMAGE
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ROOF ARCHITECTURAL STYLES - PHOTO GUIDE
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SIDING TYPES, INSTALLATION, DEFECTS
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STAINS on & in BUILDINGS, CAUSES & CURES
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STAIN DIAGNOSIS on BUILDING EXTERIORS
STUCCO WAll FAILURES DUE TO WEATHER
STUCCO WALL METHODS & INSTALLATION
STUCCO PAINT FAILURES
SURFACE GRADING, SITE DRAINAGE
THERMAL EXPANSION of MATERIALS
TREES & SHRUBS, TRIM OFF BUILDING
TRIM, EXTERIOR CHOICES, INSTALLATION
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
WALL CONSTRUCTION BARRIER vs CAVITY
WATER BARRIERS, EXTERIOR BUILDING
WATER ENTRY in buildings
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Roof drainage downspout leak points: this article describes the places where you are most likely to find leaks in the building roof drainage system downspouts or leaders. This article series discusses how to choose, install, diagnose & maintain roof gutters & downspouts, & roof drainage systems to prevent building leaks and water entry.
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[Click to enlarge any image]
Common leak points at downspouts include:
Sketch courtesy of Carson Dunlop Associates.
Downspouts may be split and damaged from swelling organic debris (leaves) or by freezing. The result is leaks against the building wall and foundation. Keeping a strainer at the gutter-to-downspout connection will protect the downspouts from becoming clogged and thus splitting.
Of course, if the downspout is connected to a buried drain line that is also blocked, water backing up into the downspout will, in freezing climates, still freeze and burst the downspout.
You might be surprised but the dislocated downspout "connection" shown at below-left is very common. Don't assume that the building's downspouts are all connected - it's worth a close look, especially if there are signs of water entry or dampness in the basement or crawl space.
At above right you can see two downspouts descending the building wall. The left hand unit is leaking a bit at the elbow. The right hand downspout has lost its elbow and extension, and leakage has rotted the building wall.
What is the proper direction or "female" end to "male end" of downspout joints?
The sketch at left illustrates the direction of water flow off of a roof - in this case a "flat roof" that drains to two roof scuppers.
The enlarged section of downspout connections (circled detail at lower right in the illustration) explains that downspout section connections and downspout elbow connections need to be installed so that water flow will always be directed to the interior of the next or "down-slope"
Sketch courtesy of Carson Dunlop Associates.
Our downspout extension line photos below show what happens if the downspout extension is too flat, or if it ends aimed "uphill" from the downspouts themselves: the downspout extension simply backs up and during heavy rain, spills by the building.
The photo at below left shows a black flexible 4" drain line and tee intended to conduct roof spillage away from the building. But following the drain line we found it ending pointing "up hill".
A closer look into the downspout extension connecting tee (below right) shows that the line contained standing water and was not draining.
An often hidden basement water entry problem is traced to a downspout that the building owner thought was safely handled below an attached deck or porch.
On closer inspection we may find that the downspout spills below the deck and against the building, or that an extension has fallen off, or as we show at left, the downspout extension slopes up-hill.
Notice the water stains on the foundation wall near the downspout?
Particularly because many builders construct the deck before final backfill and grading, soil below the deck slopes back towards the building, increasing the risk of basement or crawl area water entry.
Sometimes desperate measures are needed to successfully extend a downspout out from below a deck. The photos below show a combination of a downspout that was spilling below a deck, an inside building corner, and a wet basement (not shown).
Continue reading at DOWNSPOUT DEFECTS, MORE
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