Blog Archives

Tune Up Existing Insulation

Posted by on 15/ 11/ 15

The two types of insulation that are usually found in older attics are fiberglass batts and loose-fill cellulose. For batt insulation to perform at its rated level, it must be installed snug to the ceiling surface and to the edges of the framing. Any gaps or voids reduce the insulation’s effectiveness. If the existing insulation is in good condition, it can be reused.

I tune up the insulation by tightening end joints, making sure batts are tight to the ceiling drywall, and filling in any voids with new pieces of insulation.

If I’ve decided to increase the amount of insulation with more batts, I like to bring the level of the older batts flush with the top of the joists and then install a new layer of unfaced batts running perpendicular to the joists. Placed above the joists, the cross-

(co...

read more

Composite Pavement Distress—Visual Rating

Posted by on 15/ 11/ 15

Composite pavement deterioration is exhibited in a combination of some flexible pave­ment distresses and some rigid pavement distresses. The most prominent composite pavement distresses, which were defined under flexible or rigid pavement, are raveling, bleeding, rutting, corrugations, pumping, and various slab distresses.

3.8.2 Investigative Methods

If a pavement exhibits structural distresses, such as cracking, patching, potholes, faulting, etc., further evaluation may be necessary to identify the cause of the distress, the extent,

and the strength of the existing pavement system and subgrade. Roadways with high traffic volumes, especially those with high truck volumes, should also be evaluated prior to rehabilitation.

Pavement Coring...

read more

Flexible Pavement Distress—Visual Rating

Posted by on 15/ 11/ 15

Flexible pavement deterioration is exhibited in any combination of the following distresses.

Raveling. Raveling, as shown in Fig. 3.31, is the result of loss of small aggregates from the pavement surface. Raveling can be caused by oxidation of the mix, improper mix design, segregation, or lack of compaction.

Bleeding. Bleeding is the flushing of excess asphalt cement to the surface of the pavement, as evident in Fig. 3.32. Asphalt cement concrete mixtures are more prone to

Flexible Pavement Distress—Visual Rating

Flexible Pavement Distress—Visual Rating

FIGURE 3.33 Example of small pothole in flexible pavement.

bleed with hotter pavement surface temperatures. Bleeding is a result of excess asphalt cement in the mix and/or low air voids in the mix.

Potholes. One of the most common problems is the development of a pothole (Fig. 3.33)...

read more

Continuously Reinforced Rigid Pavement Distress—Visual Rating

Posted by on 15/ 11/ 15

Continuously reinforced concrete pavement deterioration is exhibited by the same dis­tresses discussed for jointed concrete pavement along with the following additional considerations.

Settlement. As previously stated, settlement as displayed by a depression in the pro­file of the pavement affects the smoothness of a pavement. It may be the result of poor construction practice such as poor compaction over a utility, poor grade control during final grading of the subgrade, or localized soil conditions that cannot resist additional overburden or increased loading. Repair methods consist of replacement to the cor­rected profile or an overlay. However, settlements are more predominant in CRC pavement, because transverse cracks are inherently more numerous...

read more

The oasis of Maryab; the great dike on the wadi Dhana

Posted by on 15/ 11/ 15

Maryab is the largest city of the region during the period of the sudarabic kingdoms. It occupies some 90 hectares enclosed by a 4.5 km wall. The site, apparently dating from the IInd millennium BC, is located some ten kilometers downstream of a gorge through which the wadi Dhana leaves the mountains. This wadi, typical of others in the region, has only occasional but particularly violent floods (twice a year, in April and July – August). Its flood flow can be as high as 600 m3/sec.

At first, partial diversions are employed to make use of water in the wadi, as is done throughout the region. Inscriptions from the 6th or 5th century BC mention the con­struction or rehabilitation of water intakes...

read more

Use special markings to help other tradespeople

Posted by on 15/ 11/ 15

It’s important to remember that the framing must accommodate plumbing, heating, and electrical features. Talk to the subcontractors before you even start on the floor. Show them your plans and find out what you can do when it comes time to frame walls so that they can do their work without having to remodel your structure.

You can start by asking the plumber whether there’s anything you can do while laying out the bathroom to make it easier to install the pipes. The plate layout for a typical bathroom is shown in the illustration below. Code requires a minimum of 31 in. from sidewall to sidewall for a toilet. The wall behind a toilet

is usuallv 12: in. from the center of the waste

/

drain. Standard bathtubs are usuallv 30 in. wide and 60 in. long...

read more

Jointed Rigid Pavement Distress—Visual Rating

Posted by on 15/ 11/ 15

Jointed rigid pavement deterioration is exhibited in any combination of the following distresses:

Surface Deterioration. Surface deterioration (Fig. 3.22) is the result of loss of cement at the surface of the slab (scaling). It is generally caused by excessive surface water and finishing practice, or the loss of both small aggregates and cement caused by abrasion from tires. Surface deterioration affects the noise level of a pavement and cannot be repaired. Surface deterioration by itself is generally of little concern.

TABLE 3.26 Pavement Coefficients for Flexible Section Design, Louisiana

Strength*

Coefficient

I. Surface course*

Asphaltic concrete

Types 1, 2, and 4 BC and WC

1000+

0.40

Types 3 WC

1800+

0.44

BC

1500+

0.43

II. Base course
read more

Earth Masonry and Other Alternatives to Frame Construction

Posted by on 15/ 11/ 15

Introduction

Most code-approved building materials in North America are manufactured using in­dustrialized processes that create components of uniform size and form, with predictable performance characteristics such as fire resis­tance, permeability ratings, insulation values, and structural properties. Since the process of testing such materials for code approval is extremely expensive, only large manufactur­ers who intend to produce, package, and sell a product for wide distribution can afford to test. This product-oriented approval process is not geared toward the analysis and acceptance of nonproprietary unprocessed natural build­ing materials and it has all but closed the door on 9,000 years of preindustrial building tech­nology.

There is at least one exception to this trend that...

read more

Water-Induced Damage in Asphaltic Wearing Surfaces

Posted by on 15/ 11/ 15

5.5.1 Introduction: The Problem of Water for Road Surfacings

Practice has shown that asphaltic wearing surfaces which are exposed to water generally start losing aggregates prematurely through a damage phenomenon that has become known as asphaltic ‘stripping’ or ‘ravelling’. Stripping is generally at­tributed to water infiltration into the asphaltic mixture, causing a weakening of the mastic, and a weakening of the aggregate-mastic bond. Due to the continuing action of water and traffic loading, progressive dislodgement of the aggregates can occur. This initial stripping rapidly progresses into a more severe ravelling of the wearing surface, and ultimately leads to pothole forming, Fig. 5.4.

Sometimes, open-graded mixtures are deliberately designed and laid...

read more

ALL ABOUT HEADERS

Posted by on 15/ 11/ 15

ALL ABOUT HEADERSALL ABOUT HEADERS

Spanning the distance above window and door openings, headers transfer the weight of the roof down through the trimmers, making it possible to have openings in a wall without compromising its strength. There are three things you need to know about headers: length, cross-sectional dimensions, and construction details.

Header Lengths

Window and door manufacturers typically provide recom­mended rough opening sizes for the prehung units they sell. To determine the length of a window header, you can simply add 3 in. to the rough opening size; this is the com­bined thickness of the trimmers that support the ends of the header.

■ The length of a door header is usually 5 in. greater than the width of the door. Therefore, a 3/0 door (36 in. wide) needs

a 41-in. header. The extra 5 in...

read more