Shingle Roof Research Articles

Evaluation of Fly Ash Stabilization of Recycled Asphalt Shingles for Use in Structural Fills

The majority of tear-off roofing shingles and manufacturing shingle scraps are currently disposed of as solid waste in landfills. Landfills are also the end place for the majority of coal combustion byproducts like fly ash. In this study, geotechnical properties of recycled asphalt shingles (RAS) stabilized with a self-cementing fly ash (FA) for use as structural fill material were systematically evaluated. Com- paction, hydraulic conductivity, compressibility, shear strength, and coefficient of lateral earth pressure at rest (Ko) of stabilized RAS were evaluated. The maximum dry unit weight (γdmax) of RAS:FA mixtures varies between 11.3 kN=m 3 and 13.8 kN=m 3 qualifying them as light- weight fill material and the compaction curves are not sensitive to water content. The hydraulic conductivity of RAS:FA varies between 2 × 10 −4 cm=s and 3 × 10 −5 cm=s for FA content varying between 0% and 20% resulting in a largely drainable material. RAS has a friction angle (φ 0 ) of 36° and cohesion (c 0 ) of 24 kPa. Addition of 20% FA reduces the φ 0 to 33° but increases the c 0 to 100 kPa making it sufficiently strong as a fill material. However, compared to compacted sand, RAS is highly compressible. Stabilizing RAS with more than 10% of FA, keeps the long-term settlement of a typical highway embankment below the typical settlement limit. Stabilized RAS has a Ko below 0.1 indicating lower lateral pressures behind retaining walls compared to typical soils. Overall results indicate that RAS stabilized with FA has potential as a lightweight material for use as highway embankment fill or retaining wall backfill. DOI: 10.1061/(ASCE)MT.1943-5533 .0000558. © 2013 American Society of Civil Engineers. CE Database subject headings: Recycling; Fly ash; Asphalts; Fills; Compaction; Embankments; Laboratory tests; Permeability. Author keywords: Recycled asphalt shingle; Fly ash; Structural fill; Engineering properties.

Moisture and Rutting Resistances of Foamed Asphalt Mixtures Containing Recycled Coal Ash or Shingles With Moist Aggregates

Abstract The objective of this study was to evaluate the laboratory moisture and rutting susceptibility of foamed warm mix asphalt (WMA) mixtures containing moist aggregates and recycled materials such as manufactured roofing shingles and coal ash material. The test properties of these mixtures included the indirect tensile strength (ITS), tensile strength ratio, flow value, and rut depth of dry and wet specimens. The experimental design included two percentages of coal ash (10 % and 5 % by weight of the aggregate), two shingle contents (5 % and 3 % by weight of the aggregate), foaming WMA and control mixtures, and two aggregate sources (containing approximately 0.5 % moisture). A total of 24 mix designs were used in this study. The test results indicate that the aggregate source significantly affected the moisture and rutting resistance, regardless of the foaming technology and/or recycled material type. In addition, the dry and wet rut depth values of mixtures containing moist aggregate generally satisfied the demand of pavement performance without requiring additional treatment. Moreover, all mixtures have high dry and wet ITS values as using recycled shingle and coal ash materials along with hydrated lime or liquid anti-stripping additive. Furthermore, the utilization of recycled coal ash and roofing shingles significantly improved the moisture and rutting resistance of WMA mixtures.

Imbricate Scales as a Design Construct for Microsystem Technologies

Spatially overlapping plates in tiled configurations represent designs that are observed widely in nature (e.g., fish and snake scales) and man-made systems (e.g., shingled roofs) alike. This imbricate architecture offers fault-tolerant, multifunctional capabilities, in layouts that can provide mechanical flexibility even with full, 100% areal coverages of rigid plates. Here, the realization of such designs in microsystems technologies is presented, using a manufacturing approach that exploits strategies for deterministic materials assembly based on advanced forms of transfer printing. The architectures include heterogeneous combinations of silicon, photonic, and plasmonic scales, in imbricate layouts, anchored at their centers or edges to underlying substrates, ranging from elastomer sheets to silicon wafers. Analytical and computational mechanics modeling reveal distributions of stress and strain induced by deformation, and provide some useful design rules and scaling laws.

Low-Volume Road WMA Mixtures: Moisture Susceptibility of Mixtures Containing Coal Ash and Roofing Shingle with Moist Aggregate

The objective of this study was to evaluate the laboratory moisture susceptibility of low-volume hot mix asphalt (HMA) and warm mix asphalt (WMA) mixtures containing moist aggregates and recycled materials, such as manufactured roofing shingles and coal ash material. These materials were tested after short- and long-term aging procedures. The test properties of these mixtures included indirect tensile strength (ITS), the tensile strength ratio (TSR), and the flow value of virgin and aged specimens. The experimental design included two percentages of coal ash (10 and 5% by weight of the aggregate), two roofing shingle contents (5 and 3% by weight of the aggregate), three WMA additives (Asphamin, Sasobit, and Evotherm), two antistripping agents (hydrated lime and one liquid antistripping agent), and two aggregate sources. A total of 72 mixtures were designed and a total of 416 ITS specimens were tested for short- and long-term aged procedures in this study. The test results indicated that the dry and wet ITS values of low-volume mixtures containing moist aggregate generally satisfied the demand of pavement without requiring additional treatment. Mixtures containing hydrated lime, in general, showed a better moisture resistance than liquid ASA for WMA mixtures. Moreover, the addition of WMA additives in the low-volume mixture was effective and generally showed a similar moisture resistance to HMA, except for when using Asphamin and liquid ASA simultaneously. Research results also indicated that the utilization of recycled coal ash and roofing shingles significantly improved moisture resistance of HMA and WMA mixtures.

Optimal design for water conservation and energy savings using green roofs in a green building under mixed uncertainties

Most water conservation and energy saving strategies for residential homes and commercial buildings have higher initial capital investment than traditional ones. Yet, the added benefits of these “green” building strategies should outweigh the increase of initial capital cost at the end of the house lifetime. Using green roof systems to cool houses gives rise to uncertainties from local precipitation patterns and the unstable market related costs and benefits. The optimal area of green roof to balance cost, benefit, and risk remains unknown. To achieve such a complex systems analysis, a grey stochastic programming model was prepared to address the optimal design strategies under mixed uncertainties. Such a cost-benefit-risk trade-off model was formulated for this study through an optimization framework to retrieve the optimal design strategies with respect to a typical Florida residential home (shingle and metal roofs). It is particularly designed to synergistically integrate a green roof with beneficial reuse of gray water and stormwater while achieving some degree of energy savings. The study identifies the optimal green roof area that keeps within the cost of a conventional home over a specific life time, such as 50 years. Research findings show that as the reliability level associated with the chance constraint was decreased, the upper bound of the green roof area did not vary much for either shingle or metal roofs. The lower bound was found to decrease in the same situation, however, due to the higher minimum cost of the cistern in relation to the greater volume of expected rainfall, forcing the required green roof area to decrease.

Performance of Warm-Mix Asphalt Mixtures Containing Recycled Coal Ash and Roofing Shingles with Moist Aggregates for Low-Volume Roads

The objective of this study was to evaluate the laboratory moisture and rutting susceptibility of low-volume hot-mix asphalt (HMA) and warm-mix asphalt (WMA) mixtures containing moist aggregates and recycled materials such as manufactured roofing shingles and coal ash. The test properties of these mixtures included indirect tensile strength, tensile strength ratio, flow value, and rut depth of dry and wet specimens. The experimental design included two percentages of coal ash (10% and 5% by weight of the aggregate), two shingle contents (5% and 3% by weight of the aggregate), three WMA additives (Aspha-Min, Sasobit, and Evotherm), and two aggregate sources. Thirty-two mix designs were performed, and 256 specimens were tested. Test results indicated that the aggregate source significantly affected moisture and rutting resistance regardless of WMA additive or recycled material type. In addition, dry and wet rut depth values of low-volume mixtures containing moist aggregate generally satisfied the demand of pavement performance without requiring additional treatment. Moreover, the addition of WMA additives in low-volume mixtures was effective and generally showed a similar rut resistance to HMA. The utilization of recycled coal ash and roofing shingles significantly improved moisture and rutting resistance of HMA and WMA mixtures.

The effect of roofing material on the quality of harvested rainwater

Due to decreases in the availability and quality of traditional water resources, harvested rainwater is increasingly used for potable and non-potable purposes. In this study, we examined the effect of conventional roofing materials (i.e., asphalt fiberglass shingle, Galvalume ® metal, and concrete tile) and alternative roofing materials (i.e., cool and green) on the quality of harvested rainwater. Results from pilot-scale and full-scale roofs demonstrated that rainwater harvested from any of these roofing materials would require treatment if the consumer wanted to meet United States Environmental Protection Agency primary and secondary drinking water standards or non-potable water reuse guidelines; at a minimum, first-flush diversion, filtration, and disinfection are recommended. Metal roofs are commonly recommended for rainwater harvesting applications, and this study showed that rainwater harvested from metal roofs tends to have lower concentrations of fecal indicator bacteria as compared to other roofing materials. However, concrete tile and cool roofs produced harvested rainwater quality similar to that from the metal roofs, indicating that these roofing materials also are suitable for rainwater harvesting applications. Although the shingle and green roofs produced water quality comparable in many respects to that from the other roofing materials, their dissolved organic carbon concentrations were very high (approximately one order of magnitude higher than what is typical for a finished drinking water in the United States), which might lead to high concentrations of disinfection byproducts after chlorination. Furthermore the concentrations of some metals (e.g., arsenic) in rainwater harvested from the green roof suggest that the quality of commercial growing media should be carefully examined if the harvested rainwater is being considered for domestic use. Hence, roofing material is an important consideration when designing a rainwater catchment.

Aerodynamic, hydro-aerodynamic and destructive testing

Hurricane-induced losses in the USA increased from US$1·3 billion per year pre 1990 to US$ 36 billion per year post 2000. In 2005, the losses exceeded US$100 billion. Hurricanes caused over 1400 fatalities in 2004–2005. Research focusing on the complex interaction between hurricanes and the built environment is therefore necessary to develop a cohesive and systemic approach to building hurricane-resilient communities. Full- and large-scale experimental research at Florida International University is focusing on the development of a hurricane wind and wind-driven-rain testing facility (generically named the ‘wall of wind') capable of subjecting single-storey building models to hurricane effects. Three different types of tests are envisioned: aerodynamic (pressure tests for low-rise buildings, rooftop equipment and mitigation); hydro-aerodynamic (wind-driven-rain intrusion through roof secondary water barriers, soffits and window/door/wall interfaces); and destructive (roof tile and shingle tests, roof fascia tests). This paper describes the new facility, provides details on hurricane wind and rain simulation, discusses the three different types of testing capabilities and states the goals of the research aimed at developing hurricane-resilient communities.

A novel technique for the production of cool colored concrete tile and asphalt shingle roofing products

The widespread use of solar-reflective roofing materials can save energy, mitigate urban heat islands and slow global warming by cooling the roughly 20% of the urban surface that is roofed. In this study we created prototype solar-reflective nonwhite concrete tile and asphalt shingle roofing materials using a two-layer spray coating process intended to maximize both solar reflectance and factory-line throughput. Each layer is a thin, quick-drying, pigmented latex paint based on either acrylic or a poly(vinylidene fluoride)/acrylic blend. The first layer is a titanium dioxide rutile white basecoat that increases the solar reflectance of a gray-cement concrete tile from 0.18 to 0.79, and that of a shingle surfaced with bare granules from 0.06 to 0.62. The second layer is a “cool” color topcoat with weak near-infrared (NIR) absorption and/or strong NIR backscattering. Each layer dries within seconds, potentially allowing a factory line to pass first under the white spray, then under the color spray. We combined a white basecoat with monocolor topcoats in various shades of red, brown, green and blue to prepare 24 cool colored prototype tiles and 24 cool colored prototypes shingles. The solar reflectances of the tiles ranged from 0.26 (dark brown; CIELAB lightness value L *=29) to 0.57 (light green; L *=76); those of the shingles ranged from 0.18 (dark brown; L *=26) to 0.34 (light green; L *=68). Over half of the tiles had a solar reflectance of at least 0.40, and over half of the shingles had a solar reflectance of at least 0.25.

The vulnerability of residential window glass to lightweight windborne debris

This paper presents the results of an experimental investigation of the momentum threshold required to damage residential window glazing when impacted by roof shingles and wooden dowels. Shingles are among the most common sources of debris in hurricane winds, and they have been observed to be a major contributor to the breach of windows. Wooden dowels represent lightweight vegetation type windborne debris (e.g., twigs, branches). Custom launching apparatuses were constructed to achieve controllable and repeatable flight modes and speeds for the debris. More than 600 annealed residential window glass specimens were tested to quantify the momentum threshold and damage accumulation. The shingle impact experiments were conducted using varying shingle sizes, flight modes, impact angles, shingle age, impact speeds, glass specimen thicknesses, dimensions, and edge boundary conditions. The wooden dowel impact experiments include varying wooden dowel diameters and angles of impact. Vulnerability curves are provided for unprotected window glass as a function of momentum, debris type, flight mode, and angle of impact.

Compact Asphalt Shingle Roof Systems: Should They be Vented?

Abstract Traditional steep-slope roof systems for the residential buildings (single-family homes and multi-building apartment or condominium buildings) consist of asphalt glass-fiber shingles applied over vented or unvented attics. The long-term performance of these roofs is primarily dependent on geographic location, proper roof ventilation, roof slope, material component selection and color, as well as proper detailing and construction. There is a trend towards maximizing interior space in residential dwellings by constructing compact steep-slope roof systems with cathedral or vaulted ceilings without proper venting of the asphalt shingle roof system, which, in turn, may reduce the life of the shingles. The primary reason for venting is to convey water vapor. Build up in the roof, to outside the building. Although few building code jurisdictions are relaxing the requirement for roof ventilation in compact steep slope roof systems, ventilation is still typically required by most building codes. Where allowed by the code, designers and contractors tend to omit the vented air space and favor the use of closed cell spray-applied foam insulations (polyurethane) or permeable insulation combined with vapor retarders to help control the build up of destructive moisture levels within the roof. This article presents the results of numerical case studies created in WUFI® that demonstrate the need for venting in unvented asphalt shingle roof systems with a variety of insulation and vapor retarder materials in a hot (Miami, FL) and cold (Boston, MA) climates. The models utilize historical hourly weather data to simulate the time-varying exterior conditions and examine the effect of natural ventilation and incidental roof leakage on hygrothermal performance of unvented and vented steep-slope roof assemblies. The interior conditions for residential buildings in the models are set at 21.1°C±1.1°C (70°F±2°F) and 35 %±15 % relative humidity. We selected the drying potential and the robustness of the moisture-sensitive roof system materials in response to incidental roof leakage to measure the performance of the roof assembly. Our study showed better durability of vented roof assemblies with permeable insulation in cold climates due to redundancies that can tolerate incidental moisture and provide visual indicators of roof leakage; roof sheathing typically dries in 1-1/2 to 2 months. All of the unvented roof assemblies are intolerant of incidental water leakage and the moisture-sensitive layers (i.e., sheathing and gypsum wallboard (for open-cell polyurethane insulation)) exceed the threshold for decay. In hot, humid climates, the most durable roof assemblies are the vented, open-cell polyurethane systems with shorter drying time of the interior gypsum wallboard when compared to the unvented roof assembly; both the sheathing and gypsum wallboard dry out within 2-1/2 months. In an unvented assembly, the drying time for sheathing is similar but the drying time for gypsum wallboard increases to 6.5 months on average. Alternatively, unvented permeable shingled roofs are a viable option in hot, humid climates, although they are slightly less durable. The least tolerant roof assemblies in either climate are the unvented closed-cell polyurethane roof assembly due to trapped moisture and slow drying of the roof sheathing (up to 12 months in Miami, FL and 27 months in Boston, MA).

Reducing waste in timber procurement is critical to replacement of original wooden shingle roofs on heritage buildings at Norfolk Island

Summary Traditional timber cutting, recovery and installation processes used by loggers and builders on Norfolk Island are a major impediment to the continued and sustainable restoration and maintenance of historic buildings at the southern tip of the island. Sustainable restoration and maintenance is likely to be a contributing factor in the expected decision by UNESCO about whether the island is included on the World Heritage List.

Use of Factory-Waste Shingles and Cement Kiln Dust to Enhance the Performance of Soil Used in Road Works

An experimental work was conducted to study the use of factory-waste roof shingles to enhance the properties of fine-grained soil used in road works. Cement kiln dust (CKD), a cogenerated product of Portland cement manufacturing, was used as a stabilizing agent while the processed shingles were added to enhance the soil tensile strength. The effects of shingles on strength and stability were evaluated using the unconfined compressive strength, splitting tensile strength, and California Bearing Ratio (CBR) tests. The results showed that the use of CKD alone resulted in a considerable increase in the unconfined compressive strength but had a small effect on the tensile strength. The addition of shingles substantially improved the tensile strength of the stabilized soil. A significant reduction in the capillary rise and a slight decrease in the permeability were obtained as a result of shingle addition. An optimal shingle content of 10% is recommended to stabilize the soil.

Fabricating and Installing Side-Lap Roof Shingles in Eastern Pennsylvania

Fabricating and Installing Side-Lap Roof Shingles in Eastern Pennsylvania

Artificial Roofing Slates and Shingles

Abstract Early in the 1980s, manufacturers started to respond to the market desires for a Class A fire-rated steep-sloped roofing material. Other manufacturers sought slate-like roofs that were lower in cost than natural slate. Both groups tried a variety of materials and cellulose fibers including fibers recovered from newsprint, bundles of wood, and more fibrous or shredded wood to reinforce portland cement matrixes. Previously, asbestos fiber was used with cement to form very durable asbestos-cement shingles, sidings, and sheets. Many manufacturers felt they could replace asbestos with other materials and did so offering performance warranties of 25 to 50 years duration. The authors have investigated and tested eleven of these artificial shakes and slates manufactured by nine manufacturers. Hundreds of roofs have been examined in more than 20 states. Some products failed before the installation was completed. Few survived past their tenth year of exposure. None of the artificial shakes and slates investigated are currently manufactured in the United States. We provide data that were generated by our laboratory tests on thousands of specimens made by nine manufacturers (A through I), identify the reinforcements present, list some of the critical properties such as flexural strength, deflection at break, and water absorption, and the specific failure modes for each product. The principal recommendation to avoid failures of this kind is to use products that have a substantial history of effective performance in the environment to which they will be used. Proceed into a market place cautiously when formulation changes are made to products with successful track records.

Policy: Chrysotile on Ice

Parties to the Rotterdam Convention, a group of more than 100 countries that have agreed to share information about hazardous chemicals, elected in October 2006 not to add chrysotile asbestos to the list of hazardous chemicals subject to right-to-know export controls. The 1998 Rotterdam Convention currently requires prior informed consent (PIC) for more than 30 chemicals, meaning an exporting nation must ensure that the substances do not leave its territory without the informed consent of recipient countries. This is the second time the Convention has declined to list chrysotile, a track record that raises serious concerns about the future of the agreement, according to Carl Smith, vice president of the nonprofit Foundation for Advancements in Science and Education. “Listing isn’t a ban,” he says. “It’s just an agreement to share information.” He adds, “Chrysotile would be on the PIC list already if the member countries would just follow through on the agreement they made when they joined the convention. If parties are going to start ignoring the Convention text, the train is off the tracks.” Chrysotile fulfills all the requirements for listing, Smith says, but unlike many of the other chemicals on the list—such as polychlorinated biphenyls, lindane, and all other types of asbestos—chrysotile is still economically important. Use of asbestos in Western countries has declined due to health concerns, but chrysotile-based products such as pipes and roof shingles are still widely used in the developing world. Trade in chrysotile is worth $600 million a year, according to a 7 November 2005 Wall Street Journal estimate. Prior to the October meeting, a panel of 31 experts on the convention’s Chemical Review Committee determined that chrysotile met the criteria for listing. Most of the meeting participants supported the proposal to list chrysotile. But Canada, Ukraine, Russia, Kyrgyzstan, India, Iran, and Peru objected and blocked action, citing either scientific uncertainty about chrysotile’s health effects or the material’s usefulness. The Chrysotile Institute, a nonprofit organization funded by the Canadian government, maintains that chrysotile is not as toxic as amphibole asbestos. Institute president Clement Godbout says the high rates of respiratory disease and cancer associated with asbestos stem from exposure to the amphibole form and to high exposures from dangerous past practices such as blowing asbestos mixtures onto walls for insulation and fireproofing. Used properly, chrysotile is a cost-effective ingredient for the cement that is often used in water pipes in underdeveloped countries, he contends. But many groups say that the concept of controlled use, particularly in developing countries, is a fallacy. Chrysotile is classified as a human carcinogen by the WHO, the Collegium Ramazzini, the World Trade Organization, and other groups. In the meantime, the parties to the Convention have deferred further consideration of the issue until their next meeting in 2008.

Quantifying rain noise on three different roof structures

A system for measuring rain noise has been constructed, consisting of a 3.4‐m3 structure with a slanted roof and an artificial rain generation apparatus using PVC pipes and an appropriate spray nozzle. Three different roof structures have been tested for the level of rain noise generated within the structure: a shingle roof, one made with an EPDM membrane, and a corrugated metal panel roof system. Measurements show that the shingle and EPDM membrane roofs perform approximately the same and outperform the corrugated metal panel system by at least 13 dB across the frequency bands of 250 to 5000 Hz. The test system and detailed results are presented, as well as compared to guidelines provided in a draft ISO standard on measuring rain noise. [Work supported by UNL UCARE Grant.]

The matrix of ancient biofilms modulates stress tolerance

From an evolutionary and ecological perspective the Cyanobacteria are of particular interest. Why is one of the key Precambrian organisms still one of the most important groups of phototrophs today? The hypothesis that the morphology and physiology of cyanobacteria has evolved little, or not at all, over thousands of millions of years, remains unproven. What does seem likely is that the success of desiccation-tolerant cyanobacteria stems, in large part, from a capacity to withstand multiple and superimposed environmental stresses. A knowledge of how these organisms accomplish this feat is thus of fundamental significance to microbial ecology, physiology and evolution. Our work aims to understand the overall effects of complex environmental stresses on the diversity, metabolism, and genome structure of cyanobacterial biofilms. Our perspective is that these communities are ancient biosensors that facilitated the rise of the cyanobacteria and their subsequent success in diverse extreme environments. Observations of polymorphic peptides in native extracellular water stress protein (WspA), polymorphic wspA sequences from different colonies, presence in WspA of primary sequences that are the most susceptible to deamidation, and genetic heterogeneity of the single copy wspA gene from different sources of Nostoc commune strongly supports the hypothesis that a single Nostoc colony may contain multiple, if not a continuum, of morphotypes. Similar diversity is displayed by Gloeocapsa spp., the predominant cyanobacteria found on asphalt shingle roof communities of worldwide distribution. Extension of this concept infers that the global diversity (and plasticity) of one “organism” may be enormous, with profound inherent regulatory consequences.

Use of asphalt roofing shingle waste in HMA

Like other construction materials, shingles have their own service life based on raw materials, production method and environmental and climatic conditions. At the end of their service life, shingles need to be replaced. However, these old shingles together with manufacturing scrap and handling waste require large storage areas and pollute the environment in time. Hence, additional usage of shingle waste is desirable. In this study, shingle waste in amounts of 1%, 2%, 3%, 4% and 5% by weight was added as an additive to asphalt concrete mixes prepared with the optimum binder content which yielded the best stability value was 5%. After determination of the optimum percentage of shingle to be added, rutting tests were performed on the specimens. Taking into account, the binder content existing in the shingle, mixtures were prepared with the reduced binder content by 0.5% and 1.0%. Test results show that waste shingles can be used in HMA as an additive to improve the Marshall stability and rutting resistance of the mixtures.

Small Rooms in Time

Small Rooms In Time Ted Kooser (bio) Several years ago, a fifteen-year-old boy answered the side door of a house where I once lived, and was murdered, shot twice by one of five people—two women and three men—who had gone there to steal a pound of cocaine. The boy died just inside the door, at the top of a staircase that led to the cellar where I once had set up my easel and painted. The robbers—all but one still in their teens—stepped over the body, rushed down the steps, and shot three people there, a woman and two men. Somebody called the police, perhaps the people who rented the apartment on the second floor. The next day's front-page story reported that the three in the basement were expected to survive. The boy's father, who was somewhere on the first floor and out of the line of fire, had not been injured. It's taken me a long time to try to set down my feelings about this incident. At the time, it felt as if somebody had punched me in the stomach, and in ways it has taken me until now to get my breath back. I'm ashamed to say that it wasn't the boy's death that so disturbed me, but the fact that it happened in a place where my family and I had once been safe. I recently spent most of a month building a Christmas surprise for my wife, a one-inch to one-foot scale replica of her ancestral home in the Nebraska sandhills. The original, no longer owned by her family, was a sprawling fourteen-room, two-story frame house built in 1884. Her great grandparents and grandparents lived there. Her great aunt, still living and 108 years old at the time I am writing this, was born there. Her father and his brothers and sister chased through those rooms as small children, and as a girl my wife and her younger sister spent summers there, taking care of their invalid grandmother. [End Page 1] Day after day as I worked on this dollhouse, pasting up wallpaper, gluing in baseboards and flooring, I would feel my imagination fitting itself into the little rooms. At times I lost all sense of scale and began to feel grit from the sandhills under my feet on the kitchen linoleum, to smell the summer sun on the porch roof shingles. I had never lived in that house but I lived there during those moments, and as I worked, the shadows of wind-tossed trees played over the dusty glass of the windows. Now and then I would hear footsteps on the porch, approaching the door. Immediately upon seeing the dollhouse on Christmas Eve, my wife began to recall the way it had been furnished when she was a girl, to talk about this piece of furniture being here and that one there. I watched her feed the goldfish in the dirty aquarium and sit down on the stiff, cold leather of the Mission sofa. I saw her stroke-damaged grandmother propped in her painted iron bed under the eaves. Listening to my wife, watching her open the tiny doors and peer into the tiny closets, I began to think about the way in which the rooms we inhabit, if only for a time, become unchanging places within us, complete in detail. I clipped the article about the shooting and must have read it a hundred times those first few days. In a front-on photograph, like a mug shot, there stood the house, sealed off by yellow police tape, looking baffled, cold, and vacant. Next to the picture was a row of slack-faced mug shots of the five arrested. They looked as empty as the house. I mailed a copy of the article to my first wife. I wanted her to share the shock that I was suffering, like a distant explosion whose concussion had taken years to reach across a galaxy of intervening happenstance. At the site where only the most common, most ordinary unhappiness had come to us—misunderstandings, miscommunications, a broken marriage...