Blog Archives

Important Considerations for Cutting Rafters

Posted by on 15/ 11/ 15

When cutting rafters, you need to consider the following four factors:

1. The length: determined by two factors— distance spanned and slope.

2. The adjustment to the length at the top and bottom. The top and bottom adjustments can depend on a number of factors and are almost always a little different. The two main factors are the distance from the true ridge or framing point, and the connection with other framing members.

3. The angle of cuts at the top, bottom, and the bird’s mouth. The angle cuts relate to the pitch of the roof and the position of the framing member the rafters are attaching to.

4. The height at the bird’s mouth. The height of the bird’s mouth can be set by details on the plans, for bearing, or to keep the roof level at the plate height.

There are many different ways t...

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The Space around the Chimney Needs a Fire-Resistant Seal

Posted by on 15/ 11/ 15

T

here’s usually a 2-in.-wide gap, required by code, between framing and masonry chimneys. To close the gap, I first stuff it with rockwool (1), then apply a bead of adhesive caulk to the framing (2). Next, I screw down wide strips of metal (recycled drip edge)
along the perimeter (3). I seal the metal to the chim­ney with fire-rated intumescent caulk (4). For continu­ity, you need to seal the ceiling joists to the drywall below and at inside/outside corners of the rough opening with expanding foam.

The Space around the Chimney Needs a Fire-Resistant Seal

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The Physical Processes Contributing to Water-Induced Damage

Posted by on 15/ 11/ 15

The existence of a water flow through an asphaltic mixture may cause desorption of parts of the mastic films which are in direct contact with the water flow, Fig. 5.8(a) carrying away elements of the bitumen[8] by advection (see Chapter 6 for a fuller definition of advection). Exposure of an asphaltic mixture to stationary water (i. e. no

The Physical Processes Contributing to Water-Induced Damage

Fig. 5.8 Schematic of physical water damage-inducing processes (Kringos & Scarpas, 2005a; Kringos, 2007) (a) Loss of mastic due to advective transport (b) Damage of the bond due to water diffusion

water flow) would, therefore, show no advective transport damage...

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Fog Sealing

Posted by on 15/ 11/ 15

A fog seal is an application of a diluted asphalt emulsion to a weathered asphalt surface. It is used to seal and enrich the surface, seal out moisture, close up hairline cracks, and prevent oxidation and raveling. Fog seals are generally restricted to low-volume, low-speed roadways and parking lots, as they have a tendency to cause loss of friction for a short period of time after application. Fog seals should only be used on suffi­ciently weathered pavements that have the ability to absorb the asphalt emulsion. Fog seals should be placed on dry, clean pavements, when temperatures are warm or hot. Traffic should be kept off the fog seal until the emulsion has cured. Up to 3 h may be necessary to ensure sufficient cure. Fog seals can be expected to last as long as 3 years.

3.10...

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Crack Sealing

Posted by on 15/ 11/ 15

Crack sealing is the placement of a sealant into existing cracks of a pavement. The sealant is made of a mixture of a neat or modified asphalt cement binder, with a number of possible additives such as rubber, polyester or polypropylene fibers, or polymers. Crack sealing can be placed into routed crack reservoirs using backer rods (see Fig. 3.6) or can be placed directly over the crack using an overband technique. Crack sealing is used to minimize the intrusion of water into the pavement. By keeping water out of the pavement, erosion of the mix is kept to a minimum, deterioration of the crack is slowed, and less water is available to saturate the base materials.

There is a wide window of opportunity for cost-effective crack sealing of flexible or composite pavements...

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Skylight above a Flat Ceiling

Posted by on 15/ 11/ 15

Positioning a skylight above a flat ceiling is an inexact science. Situating the skylight between rafters is easy enough, but because lightwells flare out, sizing and positioning the ceiling opening can be tricky if you’ve never done it before. Here are a few tips to demystify and simplify the process.

► Use a pencil or painter’s tape to roughly outline the lightwell opening on the ceiling. Push nails up through the corners of the opening so you can spot them from above.

► Go into the attic or crawl space above to find the four corner nails and determine if there are wires, pipes, and ducts that would be a problem to relocate. Avoid positioning skylights where roof planes converge, by all means. It’s far easier to reposition the skylight.

► If the space over the ceiling is inaccessible, tu...

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Stage 3: Determining Air Voids in a Compacted Coarse Aggregate

Posted by on 15/ 11/ 15

The Americans have undertaken analyses on the usefulness of various methods of testing for contact between coarse particles. Ultimately, they have settled on the dry – rodded test according to AASHTO T 19-00 (Brown and Haddock, 1997). It has also been standardized as ASTM C29-97.

Let us remember what we are considering now; we are looking for the content of air voids among the compacted coarse particles that make a skeleton. Thus we are screening the coarse aggregate (regarded as the active fraction) of each of three trial aggregate mixes (three design gradation curves of Stage 2) through the boundary sieve (BP sieve) selected in accordance with the NMAS. Furthermore, three such screened samples of the coarse aggregate will be tested according to the dry-rodded method.

What does the dry-ro...

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PAVEMENT PREVENTIVE MAINTENANCE

Posted by on 15/ 11/ 15

Preventive maintenance (PM) is a cost-effective strategy of early maintenance done to a pavement as a preemptive measure to preserve the pavement by retarding deterioration. PM is traditionally a low-cost treatment done early in a pavement’s deterioration cycle. By definition, pavement preventive maintenance extends the service life and maintains or improves the functional condition of the system without substantially increasing struc­tural capacity.

Pavement PM treatments reduce the amount of water infiltrating the pavement structure and correct surface deficiencies such as roughness and non-load-related distress. These treatments contribute little or no improvement to the pavement structure. PM should never be applied if fatigue-related distress exists in the pavement.

If applied at t...

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Other fittings 9

Posted by on 15/ 11/ 15
In last article we got acquainted with a spring safety valve. It is possible to consider such design as the most vserasprostranenny, on the last measure, for introduction in a life. But without considering a spring drive other designs were extended also. Namely read more

STEP5 Build the Walls

Posted by on 15/ 11/ 15

In addition to being a carpenter for the past 50 years, I’ve also been a gardener my entire life, and I see a lot of similarities between framing and gardening. If you take the time to prepare the ground, add lots of compost, plant good seeds, mulch well, and nurture young plants, you can’t help but grow out­standing vegetables. The situation is similar when you’re framing walls, if you take the time to lay out, cut, and correctly position every part of every wall, then the actual fram­ing will go smoothly and you’ll produce a quality building.

A Habitat volunteer once said to me, “Now the fun starts,” as we began to nail together all the wall pieces. I guess everything in life is rel alive...

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