Restorer's Guide The Where and The Why


It is important to know why and where a particular element has failed prior to the establishment of the "how."


Defining a detailed scope of work on an element by element basis allows the owner/building manager, and contractor to get a realistic handle on costs, time and materials required, and feasibility of repair vs. replacement. Simply stating "repair as required" leaves a great deal to individual interpretation resulting in wide differences in the contractor's bids. This ambiguity causes schedule delays, compromise of quality, and costly change orders.


The basic criteria for a comprehensive inspection can be categorized in two basic conditions:



1 The Condition of the Paint


Paint is the first line of defense to moisture and sun degradation. Often the assessment of a building's condition is made strictly from the quality of the paint film. Usually only 5% to 10% requires repair. Paint failures are usually related to age or sub-



The older alkyd and linseed oil based paints turn brittle over time resulting in the alligatoring and chalking of the paint film. Peeling paint often signals poor surface preparation or high moisture content levels. Use an adhesion test to analyze the bonding quality of the paint.



2 Substrate Condition


When inspecting the condition of the exterior elements, it is important not to rely strictly on visual clues. Probing with an awl or pen knife will allow one to "see" beneath the paint film and examine the condition of the underlying substrate. Modern paint systems allow considerable moisture to penetrate without exhibiting any outward signs of failure.


Sills, bottom rails, lower brick moldings, porch columns, and wooden gutters are most effected. Exposed end-grain, open joints, checks or fissures, and cracked glazing compound all permit moisture to penetrate below the surface. The quality of old growth wood can take considerable moisture and ultra-violet light and show only surface degradation. Just a 1/4" to a 1/2" below the surface may lie some very solid material.



Increasing evidence of past attempts at repair are discovered. Due to differences in expansion and contraction, dutchman splices often de-adhere and promote decay of the surrounding area.

Brittle repair materials, together with inadequate surface preparation, cause adhesion and cohesion failure.

Based on this comprehensive inspection, the building owner/manager and contractor now possess the information necessary to assess where and why the failures have occurred. The simple step now becomes translating the findings into the marching orders needed to get the job done.


Windowsill Repair: Q: "Should I repair my windowsills?"
By General Contractor Tom Silva, This Old House Magazine

How to Fix Rotted Wood with Epoxy

Saving a rotted window with This Old House general contractor Tom Silva
With general contractor Tom Silva, This Old House Television