Blog Archives

Cracking of SMA Course When Rolling

Posted by on 21/ 11/ 15

Cracking of the mixture under rollers may be observed when there is no bond between an SMA course and the layer under it or when the temperature of the SMA mixture is too high. The temperature of the mixture during compaction is easy to control, therefore it will not be a topic of this section.

Figure 11.32 shows an old cement concrete pavement without a tack coat covered with a new SMA overlay. This resulted in a “dry slide” and the tearing of the SMA.

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FIGuRE 11.32 An example of the tearing of an SMA mat due to the lack of a tack coat on the cement concrete bottom layer. (Photo courtesy of Krzysztof BlaZejowski.)

A similar accident might happen while paving SMA on an old asphalt course with a very polished surface...

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Roof Timber Framing for the Rest of Us

Posted by on 21/ 11/ 15

Подпись: Fig. 4.39: This was the post-and- beam frame for Log End Cottage. The ridge beam was a recycled eight-by-ten and already notched to receive the three-by-ten rafters, not shown. The roof slope is 8:12. Drawing by Marie Cyburt Taluba.image81Ridge beam. I cannot hide my love for a substantial ridge beam (also called, correctly but oddly, a ridgepole), and Гт not talking about the comparatively flimsy ridge “board” used by most stick-frame builders. No, I like something like the eight-by-ten at Log End Cottage (Fig. 4.39) or the ten-by-ten at Log End Cave (Fig. 4.40). Both of these houses were designed to support heavy earth roof loads, so the ridge beam spans were limited to about ten feet. Internal posts can be “free­standing,” where they are not in the way, or they can be incorporated into a wall and become integral with the floor plan. At Earthwood, we have two free-standing posts, one each story, and we learn to live and work around them...

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Improving Drinking Water Quality with Reverse Osmosis

Posted by on 21/ 11/ 15

Pure water is one of the three essentials of life. The Bau-Biology approach is always to look first to nature. For water, we can look to the seagull. In 1969, Steven Sourirajan, professor of environmen­tal studies at the University of California, discov­ered thatthe seagull has a special membrane in its throat that enables it to drink salt water. The mem­brane allows water to be absorbed and the extra salt is then spit out through the nasal passage.

This observation allowed Sourirajan to de­velop the first reverse osmosis water purifier. To­day reverse osmosis has been developed into a marvel of modern water purification technology and is being used all over the world. It has become the most effective method ever invented for wa­ter purification...

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Countertops for Kitchens and Baths

Posted by on 21/ 11/ 15

Most materials in this section require special training and equipment for installation. In fact, solid-surface and stone-polymer countertop mak­ers will sell counter stock only to certified fabri­cators. Some materials, such as plastic laminates, can be successfully installed if you’re handy. But,

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The dining area does double-duty. Both bench seats have built-in hanging file cabinets, so the owner can sit at the table and deal with household bills. And under the butcher-block top, a small end drawer holds flatware.

 

Countertop Choices

CHARACTERISTIC

PLASTIC

LAMINATE

SOLID

SURFACE

QUARTZ

COMPOSITE

CERAMIC

TILE

STONE

CONCRETE

WOOD

Durability, scratch resistance Fair

Excellent*

Excellent

Good

Goodt

Good

Fair!

Ease of cleaning

Excellent

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INSTALLING WALL CABINETS

Posted by on 21/ 11/ 15

Wall cabinets must be leveled, plumbed, and solidly anchored, so transfer the locations of stud centers to the back of each wall cabinet, and predrill screw holes in the mounting rails, as you did for base cabinets. Remove the doors and shelves so the cabinets will be easier to lift and position next to the alignment marks you drew earlier along the wall cabinet layout line. Before lifting anything, however, use a 6-ft. spirit level to refresh your memory as to where the wall’s surface is out of plumb and where it bulges or recedes. Make light pencil notations on the wall.

Supporting cabinets. It’s better to have a helper hold wall cabinets in place as you mount them. But if you’re working solo, the simplest support is a temporary support strip, a straight, predrilled M-in. by Hi-in...

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Transverse porosity

Posted by on 21/ 11/ 15

Transverse (or lateral) porosity can often be seen on pavements made during unfa­vorable weather conditions (in autumn or in winter) or when the mixture has been

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FIGuRE 11.25 Beginning of a work site—effect shown years later, a consequence of spreading too cool a mixture at the beginning of the work site. (Photo courtesy of Krzysztof BlaZejowski.)

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Подпись: <68

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FIGURE 11.28 Local porosities: (a) an infrared image; (b) the effects after a couple of years on another road that has the same problem, arrows point at spots of pavement pot holes occurring at cyclic distances. (Photos [a] courtesy of Kim A. Willoughby, WSDOT, United States; [b] courtesy of Krzysztof Blazejowski.)
transported from far away...

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The parts of a gable roof

Posted by on 21/ 11/ 15

The parts of a gable roof

the span. When you know the pitch of a roof plus the true span (measure the span from outside wall to outside wall with a long tape) or the run, you can determine the length of the common rafters. To do this, try using a book of rafter tables (see Sources on p. 198) or a pocket calculator.

A 24-ft.-wide building has a span of 24 ft. To find the rafter length of a 4-in – 12 pitch roof for this building, open your rafter-table book to the 4-in-12 page and look under the common-rafter table
at 24 ft. to see that the rafter length is 12 ft. 73/д in. If the span is 24 ft. 8 in., look under 8 in the inches column and add on an extra 41A in. That is the total length of the common rafter. It’s really that simple, so don’t make it difficult for yourself...

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The great reservoirs of Ceylon

Posted by on 21/ 11/ 15

About 544 BC the island of Ceylon (Sri Lanka) falls under the domination of princely families of Indo-European origin, coming from Maghada. The Ceylonese civilization develops markedly after the conversion of the island to Buddhism. This conversion is attributed to a certain Mahendra who, according to tradition, is said to be the son or the brother of the great king Afoka. Irrigation is a significant factor in the island’s develop­ment. Rainfall is abundant, but concentrated during the monsoon period. Since the soil is relatively impervious, very little of the rain is stored as groundwater. The only solu­tion is construction of dam-reservoirs.

We can identify several reservoir-dam installations dating from 370 BC to 540 AD...

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KEEPING COLD AIR FROM ENTERING. AT THE RIM JOISTS

Posted by on 21/ 11/ 15

Подпись: To keep cold air from entering on top of the floor insulation, ensure that insulation is right up against the subfloor (above, left) or roll the insulation up the inside of the rim joist to the subfloor (above, right). Either of these techniques will help prevent a cold floor. Helping Hand

Store fiberglass scraps in a garbage bag. Spare and scrap pieces of fiberglass can easily blow all over a job site. To keep this fluffy material under control, put it in a large plastic garbage bag. Partial rolls can also be stored in a plastic bag until needed.

Подпись: SUPPORTING INSULATION BETWEEN FLOOR JOISTSПодпись:Подпись: InsulationПодпись: Wood lath nailed to the bottom of the floor joists 12 in. to 16 in. o.c.Подпись: Metal rods between joists about every 12 in. o.c.Подпись: Plastic mesh or landscape cloth stapled to the underside of the joistsKEEPING COLD AIR FROM ENTERING. AT THE RIM JOISTS

STEP 3 Install Vapor Barriers (if Necessary)

Unlike housewrap, a properly installed vapor barrier is supposed to be impermeable. Vapor should not pass through it. Different materials are used as vapor barriers. The kraft-paper facing on fiberglass batt insulation is designed to function as a vapor barrier. To form a con­tinuous barrier, the paper flanges must over­lap on the sStud face, where they are stapled in place. Polyethylene sheeting is also commonly used as a vapor barrier...

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STEP 2 INSULATE THE WALLS, CEILINGS, AND FLOORS

Posted by on 21/ 11/ 15

Although the reason for sealing cracks and gaps in a house frame may be fairly obvious—you don’t want cold breezes (or hot air, depend­ing on where you live) blowing through the house—the function of insulation may not be as evident. It is not to block airflow but rather to create pockets of dead air. Air pockets do the actual insulating work, whereas the insula­tion fibers or beads simply hold the air in place. That’s why jamming fiberglass insulation into a too-small space isn’t very helpful. In fact, doing so just eliminates much of the air space within the material, effectively reducing its value as insulation.

There are a number of materials used for insulation, but the three most common ones are cellulose, rigid foam, and fiberglass.

Subcontractors most often install cell...

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