Asphalt sided home in Two Harbors MN (C) Daniel FriedmanAluminum Siding Inspection, Defects, Diagnosis, Repair Advice

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Aluminum siding inspection, diagnosis, repair:

This article discusses the identification, history, and common defects observed in aluminum exterior building siding, such as weathering, paint loss, dents, and questions about the need for a vapor barrier behind asphalt siding and over building sheathing. Included are comments from several recognized building inspection and construction authorities.

Our page top photograph shows 1960's vintage (wideboard) aluminum building siding installed over peeling deteriorated wood clapboards on a pre-1900 home in Poughkeepsie, NY.

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Aluminum Siding History, Defects, Vapor Barriers, Inspection, and Diagnosis

Buckled siding at ground level indicates sill crushing (C) Daniel FriedmanAluminum & steel building siding was very popular and widely installed in North America from the 1940's into the 1970's. Because of the large amounts of energy used to produce aluminum siding and increasing raw materials costs, aluminum siding declined in popularity in the U.S. in the 1970's.

Aluminum siding, produced from aluminum coil stock and painted in a wide variety of colors, provided a durable exterior building cladding that resisted rust and rot. Aluminum siding in its earlier forms was typically produced in a (roughly) 6" wide clapboard stock, installed with a fiberboard backer to resist denting in some cases.

By the 1970's a narrow-width aluminum siding "board" stock was in popular use in both smooth surface forms and in embossed designs resembling wood.

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How to Identify Aluminum Building Siding

It's easy to distinguish between aluminum siding and vinyl siding products by careful visual inspection of the material edges or by observation of dents (aluminum) versus breaks or impact damage (vinyl). But to distinguish between aluminum siding and it's steel look alike you may need a magnet (or you might see rust).

Aluminum Siding Inspection, Defects, & Maintenance Suggestions

Building siding in ground contact: risk of insect damage or rot & structural damage

Damaged aluminum siding (C) Daniel Friedman

Don't install any building siding down in contact with the soil or below the soil level (below left) - doing so is inviting a hidden termite or carpenter attack. On occasion we have inspected a building whose bottom course of siding was bulged outwards.

Knowing that it would have been virtually impossible to install the siding in that form, a good guess is that the building sills and or lower walls have been damaged by rot or insect pests.

Our siding photo at below left shows a roof gutter downspout spilling right by the aluminum siding that has been buried below ground level. Adding water increases the risk of hidden insect or rot damage.

This often hidden condition and the need for possibly costly building repairs can be verified by interior inspection or by removing some exterior siding at the wall bottom. This is not a defect peculiar to aluminum, vinyl, or other siding products - you can make this mistake with any wall cladding.

Buckled siding at ground level indicates sill crushing (C) Daniel Friedman

Buckling Aluminum Siding at Ground Level Means Big Trouble

The condition of building siding may be more than a cosmetic issue. For people interested in detecting hidden building damage the photo at left is one of the more important ones we've taken.

This aluminum siding photograph illustrates buckling aluminum siding at the wall bottom - not a defect in the siding material but a poor installation (buried in the ground) inviting insect and rot problems in the building structure.

The aluminum siding is buckled in the bottom two courses on this home but is intact on upper courses. The building, built over an inaccessible crawl space had suffered such extreme termite damage to its sills and lower wood-framed walls that the weight of the building above had crushed and buckled the aluminum siding.

An understanding of how siding is installed on buildings (from the bottom of the wall up) would lead an observer to realize that you couldn't install buckle siding in this fashion, the damage had to occur by a downwards movement of the structure (or an earth heave which was very unlikely in this pattern). Very extensive and costly sill and wall framing repairs were needed - an opinion confirmed when the lower siding segments were removed.

Comparing Aluminum Siding Wide and Narrow Widths

Our aluminum siding photo (below left) provides a close up of 1960's vintage aluminum siding that is losing its paint coating.

The right hand photo shows a nice algae growth on this shaded, aluminum-sided building wall that was covered with a narrow-gauge wood-pattern embossed aluminum siding product in the 1980's.

Damaged aluminum siding (C) Daniel Friedman Damaged aluminum siding (C) Daniel Friedman

Paint loss on aluminum siding

Watch out: some versions of aluminum siding (especially from the 1960's) included a paint coating that weathered, chalked, and even washed off entirely, leaving a bare aluminum surface (photo below left).

The painted coating on some aluminum siding can also be "pulled" off of aluminum siding by some fungal growths (artillery fungus) and by vines (photo below right).

Damaged aluminum siding (C) Daniel Friedman Damaged aluminum siding (C) Daniel Friedman

Cleaning or Painting Aluminum Siding

Damaged aluminum siding (C) Daniel Friedman

Our aluminum siding photo (at left) shows a close up of a fungal growth on an embossed aluminum siding product. The mold growth on this siding is not a product defect, it is the result of site conditions - moisture and shade.

Aluminum siding (and other siding products) can be cleaned by power washing or by hand.

Watch out: don't spray your power washer "up" under any building siding product or you risk blowing water into the building walls, causing a mold or water damage problem.

Painting weathered aluminum siding

With careful surface preparation and selection of a paint recommended by its manufacturer for aluminum siding, it is possible to re-paint weathered aluminum siding - of course we then have converted a "no maintenance" material into one that will require occasional repainting.

Steel Building Siding

Steel building siding was sold based on advantages similar to aluminum siding (see Aluminum siding) but with disadvantages of heavier weight, more difficult to install (harder to cut and trim), and vulnerable to rust. Steel siding was never as popular in North America as aluminum nor its later replacement - vinyl.

Photos and notes on steel siding are wanted - CONTACT US.

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