(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Roof, 6.Close, 7.MEP, 8.Finish)

The availability of standard milled framing materials, structural connectors, and skilled carpenters makes traditional wood framing the obvious choice for most types of residential construction. Wood framing resources include print publications and online information common to an industry of contractors, subcontractors, and material suppliers.

Setting Main Ridge Supports
In this example, the ridge beam column supports are built into the gable walls at each end of the open ceiling. The walls are framed so that the sloping top plate matches the height and slope of the roof rafters.

Framing Phase – Insitebuilders

When floor space is limited, the walls are fabricated on the lower level and lifted with a portable material hoist that can be rented from most equipment rental companies, see http://www.genielift.com for specifications and information.

Framing Phase – Insitebuilders

The gable walls are set to vertical and stabilized with braces or framed into adjacent shear walls so that they remain ridged and in place while the main ridge and header beams are lifted into place.

Final structural review
The structural integrity of a wood frame house is also easier to inspect and maintain. Most of the connectors and straps required for tie down can be installed after the floor and wall framing are complete. The size and placement of structural connectors varies with location and building loads.

Framing Phase – Insitebuilders
As a structural system, construction began with the installation of securely anchored pressure treated sills. The floor joists are then strapped to the sills and the foundation walls and the walls strapped to the joists. Interlocking top plates then tie the walls together to create a solid structural frame.

Once the walls and connectors are in place and inspected, exterior sheathing is installed with nails spaced according to code requirements. The sheathing further stabilizes the frame prior to beginning the roof framing.

Trusses Roof Framing
Most residential designers and contractors prefer placing concrete as a slab on grade and installing prefabricated roof trusses because they are much faster and cheaper than field framing a raised floor and open ceiling (see the Wood Council of America research results at www.wtca.org)

Framing Phase – Insitebuilders

  • Prefabricated trusses are economical for large floorplans
  • Less skilled labor required
  • Roof components are computer engineered
  • Simple and fast to erect with a placement plan
  • Quality controlled manufacturing reduces waste
  • On center spacing maximized to reduce materials
  • Long clear spans reducing interior bearing walls
  • Saving in roof labor and material mean less energy consumption
  • Reduced man hours, lower risk, overhead and worker insurance

Conventional Roof Framing

A conventionally framed roof is assembled in the field using off-the-shelf materials. The key advantages are found with smaller houses where reduced labor and faster production have less of an impact and are not a primary consideration (Note that predesign requires careful detailing and coordination with mechanical, electrical and plumbing systems).

Framing Phase – Insitebuilders

  • Best for smaller, custom homes with open spaces and ceilings
  • Framing materials are readily available from lumber suppliers
  • Open rooms and variable ceilings
  • Custom design features like clerestories and gables
  • Open interior sight lines
  • Greater square footage efficiency under the roof
  • Upper volume of house available for special features like lofts
  • Field control of framing details to simplify roof lines
  • Traditional style and design details for interior and exterior

 

(To be continued…)

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The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Framing Phase – Insitebuilders

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(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Roof, 6.Close, 7.MEP, 8.Finish)

Safety planning that started before the project began becomes increasingly important as the house rises out of the ground. Limited floor area, sloping surfaces, and overhead work combine with the height of the upper floors and roof framing to make fall protection, setbacks, work zones, and barricades especially important.

Working safely
To minimize possible injury, lead carpenters coordinate cutting and framing activities, monitoring the use of saws, nail guns, hoists, ladders, and scaffolding for both the main and upper work areas. For this reason, whenever possible, rim and floor joists are installed from step ladders or rolling scaffolding to reduce the possibility of falling tools, materials, or workers.

Framing Phase – Insitebuilders

Headers and beams bear on the double top plates of the main floor wall framing and the embedded columns. Once in place, they are secured with clips, straps, or fasteners at the beam pockets, following engineering specifications and local building codes.

Framing Phase – Insitebuilders

Sheathing for the shear walls is nailed continuously across the upper floor framing to maintain lateral resistance within the structural frame. The upper floor joists are then placed to “sandwich” the vertical shear wall into the floor framing before the subfloor is installed.

Framing the entry roof
Structural connections require special attention when freestanding roofs extend over open areas beyond the plane of exterior shear walls. For example, in this tutorial the entry roof is open on three sides and exposed to lateral and uplift loads. This leaves the framing vulnerable to the environment, loads from wind, earthquake, rain, snow and insect damage.

Framing Phase – Insitebuilders

This exposure also makes it important to install the framing members using tie down straps, as well as post footings with base brackets that compensate for uplift and moisture penetration. Engineered structural connectors are again required by building codes in most jurisdictions (See Simpson Strongtie).

Framing Phase – Insitebuilders

Before the sheathing is finalized, carpenters add blocking between the floor joists to stiffen the frame at center span and bearing positions. Solid blocking is installed at post or column bearing points to carry loads through the upper floor framing to the foundation or girder beam below.

 

(To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders.com

Framing Phase – Insitebuilders

Part 24: Interior Wall Framing

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Roof, 6.Close, 7.MEP, 8.Finish)

Once the perimeter walls are in place and the first floor platform is secure, the interior walls are ready to be installed following the layouts shown on the floor plan.

Assembling the interior walls
Field carpenters determine the order of installation for the walls based on the working space available for assembly. Keep in mind that the chalklines on the subfloor mark the location of walls and top and bottom plates have already been cut to fit the line intersections.

Framing Phase – Insitebuilders

Schedules found on the construction documents list rough openings for the doors and windows. Header sizes for these openings vary with the span and the loads from the upper floor and roof framing. Structural headers and supporting columns that must be extended to the foundation are noted on the construction documents for special consideration.

Framing Phase – Insitebuilders

Bottom plates framed into the walls at the threshold of all the openings are cut after the double top plates for the upper floor framing have been finalized.

Filling in the details
Connections at the intersection of wall corners and end points are especially critical to stabilize the wall framing. The floor plan shows the location of the walls, but field crews determine how they interlock to prevent stress cracking once the interior materials are in place and finalized.

Framing Phase – Insitebuilders

The bottom plates of the walls that run perpendicular to the floor joist are nailed through the subfloor into the top of each supporting joist. When the walls run parallel to the joists, additional blocking may be required to prevent deflection.

Framing Phase – Insitebuilders

Lead carpenters are particularly aware of the need for blocking between the floor joists for columns, posts, and bearing walls. Solid blocking provides full bearing for structural loads that must be transferred from the upper floor and roof framing to the foundation.

Finalizing first floor wall framing
Once all the interior walls are in place, they are checked for proper nailing and structural integrity. The construction documents are used to check for missing connectors and excess nailing at the plates and studs. Too many fasteners or missing connections reduce the strength of the overall frame.

Framing Phase – Insitebuilders

When tie down straps and structural connectors are finalized the lower floor framing is ready to be tied together with the doubled top plates. Placement and specifications for these connectors vary with local conditions, see the National Association of Home Builders resources at http://www.toolbase.org for design guidelines.

Framing Phase – Insitebuilders

The top plates are installed to lap over adjacent walls so that they lock the framing together as a single structural unit. The additional top plate also strengthens the span between the studs making them less likely to deflect under loads from the upper floor and roof framing.

 

(To be continued…)

—————————
The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

insitebuilders.com

 

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Roof, 6.Close, 7.MEP, 8.Finish)

The construction method shown in this SketchUp process model is called “platform framing” because the interior is enclosed by wood studs, spaced to carry vertical and lateral loads as a lightweight space frame and the top plates of the walls are installed as a platform to carry the upper floor and roof loads.

Outside wall thickness
Engineers specify spacing and stud sizes to support the structural loads acting on the house and local indoor air quality requirements. The thickness of the outside wall is therefore a function of the depth of the stud, with the space between the studs used for loose, batt, or foam insulation.

Framing Phase – Insitebuilders

For safety, the walls are braced against wind load or accidental collapse as they are assembled and moved into place. The erection sequence and details at the corners and openings are determined in the field by the lead carpenter.

Framing continues around the perimeter
Framing details around the doors and windows for the outside wall accommodate the stud sizes, wall thickness, and the loads carried by the shear panels and headers specified by the engineers.

Framing Phase – Insitebuilders

The top plates over the wall studs distribute upper floor and roof loads to the vertical members in the walls and the bottom plates and the floor joists below the subfloor.

For detailed information about wood framing methods and load tables, see the American Wood Council publications and guides at http://www.awc.org.

Framing Phase – Insitebuilders

Nailers used to attach interior and exterior materials, cabinets, built-ins, shelving, and brackets are framed into the walls. The size and placement of these nailers depend on the weight and locations shown on the floor plans.

Finishing the outside wall framing
Sheathing is nailed to the studs as the walls are being erected in areas that will be difficult to access once all the walls are in place. It would be a mistake to sheath all the outside walls before interlocking top plates and interior walls are installed because the frame would be inadvertently exposed to wind loads during construction.

Framing Phase – Insitebuilders

Safety is improved once all the perimeter walls are in place because they act as a guard rail around the work area. This is especially important in framing the upper floors of a larger building.

Framing Phase – Insitebuilders

Next, the outside walls are strapped to the floor framing and foundation. Note that details for the framing around the openings and the outside corners of the outer walls follow standard framing details that distribute structural shear and bearing loads to the floor and foundation.

Framing Phase – Insitebuilders

Standard structural connectors are used to tie the walls to the rim joists of the floor framing (See the Simpson Strongtie Catalog for wood construction). Spacing and location of these tie-down straps are specified by engineering calculations and the local building codes.

Tie-downs and sheathing are important because wind and earthquake loads will generate positive and negative pressures causing dynamic uplift and rotational stresses on the completed frame.

(To be continued…)

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The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders.com

Part 22: Shear Wall Framing

December 15, 2014

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Roof, 6.Close, 7.MEP, 8.Finish)

The wall layouts follow the floor plan for the building’s design, but the overall dimensions of the framing as well as the framing members themselves are determined in the field by the framing crew doing the work.

Wall assembly
The construction method varies with the wall’s location, the size of the job, and the structural requirements. A full framing team is made up of a lead carpenter, framers, and at least one carpenter in charge of the actual cutting.

Framing Phase – Insitebuilders

The lead carpenter sets the layout and sequence of wall construction and the framers determine the cut lengths for the assembly as they erect the walls.

Lengths are either called immediately to a cutter as the wall is being assembled or listed on a cut-sheet so the pieces can be prefabricated as separate bundles. The pieces in each bundle are then marked for assembly and staged on the subflooring for different crews.

Framing Phase – Insitebuilders

The idea is to safely separate the work, allowing skilled carpenters to check dimensions and fit the members together as each wall is put into position.

Shear walls anchored to the foundation
Once the wall is assembled, it is tilted up and moved into place over the layout lines marked on the subfloor. The bottom plate is then nailed or bolted through the subfloor into the top of the floor joists.

Framing Phase – Insitebuilders

When regional wind or earthquake loads require special engineering, the shear walls are designed so that tie down anchors extend down to the floor framing to be bolted to the foundation.

Framing Phase – Insitebuilders

The shear walls also extend up from the foundation as part of the wall framing to be tied into the roof framing. In this way, the entire structure acts as a unified structural element. For this reason, the size and spacing of the nails securing the panels to the studs is critical to transferring lateral stiffness of the wall from the foundation to the roof.

 

(To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

http://insitebuilders.com

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Roof, 6.Close, 7.MEP, 8.Finish)

The nail patterns in the subfloor should be inspected once the floor panels are in place. Staggering the panels eliminates continuous joints in the flooring and correct sizes, penetration, and spacing of the nails ensure that the structure acts as a continuous horizontal shear plane to counteract any possible lateral or twisting forces.

Top and bottom plate layout

The walls are framed with studs equally spaced between top and bottom plates of the same width. The plates are cut to fit layout lines chalked directly on the subfloor for each wall.

Framing Phase – Insitebuilders

The plates match the length of the wall with spacing for studs, trimmers, and headers marked directly on the plates. All the pieces for the wall are precut and bundled as a package to speed final assembly. The framing for the outer walls are installed first. The studs in the outer walls are thicker to add strength and allow for insulation.

Framing Phase – Insitebuilders

The sequence of installation for the interior walls is determined by the carpentry foreman according to the location of corners and wall intersections. Studs are added at these corners and intersections as backing for wall board to be applied once the framing is complete.

Wall framing bundles ready for assembly

The framing team is composed of a cut man (or woman) at the work station in charge of bundling the pieces for each wall. A lead carpenter calls out the lengths, sizes, and pieces required for each wall and the carpenters then assemble the walls as the prefabricated bundles are completed.

Framing Phase – Insitebuilders

Each bundle includes the top and bottom plate, studs, headers, and trimmers necessary for that wall. The idea is to safely separate the work for the wall framing, allowing skilled carpenters to check dimensions and the fit of the walls before they are assembled.

Framing Phase – Insitebuilders

The members in the bundle are laid out on the subfloor with the bottom plate positioned on the wall’s layout line. Sizes are checked and the pieces are nailed together while they are flat on the subfloor.

Once assembled, the wall is tilted to stand vertically, moved into place and temporarily braced until the adjoining wall is installed. The bottom plate is then positioned exactly on the layout lines and nailed to the floor joists. Solid blocking is added whenever a plate does not bear directly on a joist.

 

(To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

http://insitebuilders.com

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Roof, 6.Close, 7.MEP, 8.Finish)

For jobsite safety, professional framers will install the plywood subfloor as soon as the joists have been secured. In high wind or earthquake zones, the joists and floor frame are strapped to the foundation at the ends of the girders and along the perimeter.

Staggered subfloor
The subfloor is laid in a staggered pattern so that its lengths are perpendicular to the direction of the joists. The plywood is then glued and nailed to the joists so the seams are centered on the length of the bearing surface.

Framing Phase – Insitebuilders

In some cases, interlocking panels and/or edge nailing to solid blocking are used to add strength to the floor framing. Solid blocking under bearing loads from above are also important.

In this example an opening is framed in the floor joists to provide access to the crawlspace. Interior access is important when you want to avoid frost lines or swales in the finish grade around the building.

Framing Phase – Insitebuilders

The enclosed crawl space is also prepared for future construction before the floor is sealed. This includes raking out rocks and debris and spreading sand or heavy mats to make it easier to service certain areas. Materials and equipment that would be difficult or impossible to put in the crawlspace are also staged for later installations.

Framing an open crawl space
The open crawlspace is framed over girders and foundation piers. The frame is again strapped to the foundation to structurally tie the frame to the foundation. Open crawl spaces allow drainage, shade, and natural circulation in warm, humid, or wet environments, but require insulation and soffits in cold climates.

Framing Phase – Insitebuilders

Access under the raised floor makes it easier to maintain or change mechanical and electrical systems, but it’s important to use pressure treated materials in extremely moist areas or if the joists are less than 18 inches from the finish grade.

Framing Phase – Insitebuilders

The crawl space is again prepared for future construction. This includes installing plumbing and mechanical systems under the floor and grading the backfill to slope away from the foundation piers and stem walls.

Finishing the open crawl space
Mechanical and electrical lines are drilled and fitted in the floor cavities before the subfloor is finalized. Here again phased construction models and careful planning help coordinate future installations, reduce costs, and speed the final construction.

Framing Phase – Insitebuilders

Once the joists are installed, insulation and soffits are fitted to the underside of the open framing. This reduces heating or cooling losses through the floor and seals the joists and insulation from moisture, insects, and other pests. Perimeter skirting prevents wild life from using the space for nests or burrows.

Framing Phase – Insitebuilders

Note that nail size and nail spacing vary with the loads imposed on the floor and the structural design of the building framework. Requirements will vary according to local codes and the loads imposed on the finished frame.

 

(To be continued…)

—————————

The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders.com

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