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The RetroRafter Roof Framing System was developed to furnish a quality alternative that requires a minimal number of vertical web members and roof penetrations yet still offers the high quality associated with the Adjust-A-Web system.

The RetroRafter System is provided with complete engineered shop drawings (including definition of the existing conditions, chalkline drawing, top and bottom member layouts, standard & special details of special conditions and notations on points of concern.) along with formal calculations and P.E. seals, when required. All material and fasteners* to assemble the framing system are provided and delivered to jobsite.

*Connections of the roof panel to the framing system and of the framing system to the existing structure typically are to be designed and provided by others.

The RetroRafter Framing System is composed of the appropriate on slope rafters, bottom members, factory cut vertical web members, top members (purlin), lateral & longitudinal strap bracing, all permanent bracing, eave members, required fascia & soffit framing, required equipment supports, gable end subgirts, etc. and the self-drilling fasteners to assemble the system.

The Truss Roof Framing System is used primarily for creating sloped roofs over new construction as well as creating sloped roofs over existing flat roofs. The trusses can be spaced up to 30'-0" o.c. and can be a true spanning truss or a frame with intermediate supports. CURA Truss Systems have the capability to span 80'-0" or more and can exceed 20'-0" in height. Trusses can be factory fabricated and shipped within transportation maximums, or can be factory pre-cut and pre-punched for assembly at the job site. CURA Truss Systems that exceed transportation maximums can be shipped in halves with factory attached webs that are nested and strapped to the top or bottom chord of the truss. Contact RRA for truss design assistance and pricing.

The Mansard Framing System can produce almost any configuration of mansard attaching to an existing vertical wall.

These systems are designed for each individual project from light gauge components and are engineered to meet the standard building codes.

The Windscreen Framing System can produce almost any configuration of windscreen to hide and protect roof top equipment.

These systems are designed for each individual project from light gauge components and are engineered to meet the standard building codes.

See RRA’s job specific drawings for Retrofit Roof Framing System fastening details and specifications.

RRA and their consultants do not investigate the adequacy of the existing structure to withstand the loads transmitted and imposed by the new roof and the Retrofit Roof Framing System. Connections of the roof panel to the new framing system and of the new framing system to the existing structure shall be designed and provided by others.

General Information
The first step in determining what fastener to use in attaching to the existing structure is to determine what the existing structural members are, the direction they run (if applicable), and the spacing of the members. These members are typically going to be steel (such as beams or bar joists), concrete (such as structural concrete slabs, hollow core planks, double tees, waffle pan deck), or wood (such as wood beams or joists). If the new bottom member is going to rest on the existing roofing material, which is frequently done, it is also important to know the thickness and make up of these materials. This will help to determine the required fastener length and whether or not a particular fastener will be appropriate. The thickness should be checked in more than one location since it can vary due to things like tapered insulation systems or partial roof repairs.

Fastener selection should be made in conjunction with someone who is knowledgeable about fasteners. RRA can provide assistance with this, as can most fastener suppliers. Making a good fastener selection requires at least the following information.

• Composition and thickness of existing structural element to be attached to.
• Composition and thickness of existing materials to be penetrated between the new system bottom member and existing structural member.
• Design loads that the fastener must resist.
• The ease or difficulty of locating the existing structural members.

Fastener selection can be done based on either pullout test or manufacturers published pullout ratings for their fasteners in various materials. These values will be dependent on the strength of the base material and either the thickness of this material or the depth of embedment of the fastener. The more doubt that exists about the existing material, the more prudent it is to conduct an actual test. In general, steel is very predictable if it is in good condition. Concrete or wood is less so because there is a much wider variation in the strength of these materials. Concrete or wood that has experienced long term exposure to trapped moisture should almost certainly be tested because of the deteriorating affects that this can have on the strength of these materials.

Pullout tests and manufacturer’s pullout tables will typically provide an ultimate pullout value. This is the load at which the connection fails. In choosing a fastener a safety factor must be applied to this ultimate value. Safety that is widely used is 3 for a single fastener connection into steel, 2.25 for a multiple fastener connection into steel, and 4 for any connection into either wood or concrete. The ultimate load value must be divided by this safety factor to determine the design load that the connection will safely resist.

The following information is compiled from numerous product manufacturers literature and should be used as a guide only. Job site conditions should be taken into consideration when determining the proper fasteners and is a responsibility of the installer or specifier. RRA assumes no liability for the use of this information.

1. Connections to METAL type structural material.

A. Examine the existing roof and structural condition.

The new roof system bottom members must be attached to the existing structural.

Pull out tests should be performed to help determine roof condition and fastener type. Contact your local fastener supplier for assistance.

Penetrations caused by pull out tests must be sealed to prevent leaks prior to installation of the new roof.

Analyze existing roof to assure that the pull out, deflection and dead loads associated with the new roof can be met. Refer to RRA’s specific job design load criteria and attachment requirements for magnitude of loads transmitted to the existing structure.

It is recommended that the existing structural be a minimum of 16 gauge to accept the new roof load requirements.

Examine the existing roof to determine roof condition and appropriate fastening method. The existing roof should be compression tested to assure that the new roof system can be supported.

B. Determine fastener requirements.

Thread length must be a minimum of 5/8” longer than the existing roof thickness.

Point type is determined by structural thickness.

Fastener strength should meet or exceed load requirements.

It is recommended that a minimum of a ¼” diameter fastener be used due to higher tensile and shear strength compared to smaller diameters.

Fasteners should be supplied with long-life coatings or be of stainless steel material for added corrosion protection.

Contact your local fastener supplier or RRA for assistance in defining the proper mechanical, physical and material properties.

C. Installation Hints.

Locate existing structure and prepare roof surface to accept the base design of the new framing system.

Apply sealant between existing roof and the underside of framing bottom members.

Install fasteners perpendicular to roof surface. Drill point failure can occur during installation if threads tap before drilling is completed.

Cover fastener with sealant to prevent leaks.

2. Connections to CONCRETE type structural material.

A. Examine the existing roof and structural condition.

The new roof system bottom members must be attached to the existing structural concrete with a minimum of 1” embedment.

Pull out tests should be performed to help determine roof condition and fastener type. Contact your local fastener supplier for assistance.

Penetrations caused by pull out tests must be sealed to prevent leaks prior to installation of the new roof.

Analyze existing roof to assure that the pull out, deflection and dead loads associated with the new roof can be met. Refer to RRA’s specific job design load criteria and attachment requirements for magnitude of loads transmitted to the existing structure.

Examine the existing roof to determine roof condition and appropriate fastening method. The existing roof should be compression tested to assure that the new roof system can be supported.

B. Determine fastener requirements.

The appropriate fastener can be a Threaded Anchor, Drive Anchor, Wedge Anchor or an Epoxy Anchor.

Choose anchor length based on roof thickness.

Fastener strength should meet or exceed load requirements.

It is recommended that a minimum of a ¼” diameter fastener be used due to higher tensile and shear strength compared to smaller diameters.

Fasteners should be supplied with long-life coatings or be of stainless steel material for added corrosion protection.

Contact your local fastener supplier or RRA for assistance in defining the proper mechanical, physical and material properties.

C. Installation Hints.

Prepare roof surface to accept the base design of the new framing system.

Drill into concrete using carbide tip wide flute bit. For best results, drill hole using a rotary hammer.

Apply sealant between existing roof and the underside of framing bottom members.

Concrete fasteners should be spaced a distance apart at a minimum of 10 diameters (example: ¼” threaded = 2 ½” minimum spacing).

Cover fastener with sealant to prevent leaks.

3. Connections to WOOD type structural material.

A. Examine the existing roof and structural condition.

The new roof system continuous bottom members must be attached to the existing wood structure.

Pull out tests should be performed to help determine roof condition and fastener type. Contact your local fastener supplier for assistance.

Penetrations caused by pull out tests must be sealed to prevent leaks prior to installation of the new roof.

Analyze existing roof to assure that the pull out, deflection and dead loads associated with the new roof can be met. Refer to RRA’s specific job design load criteria and attachment requirements for magnitude of loads transmitted to the existing structure.

It is recommended that the existing wood structure be cable of 1” minimum fastener embedment to accept the new roof load requirements.

Examine the existing roof to determine roof condition and appropriate fastening method. The existing roof should be compression tested to assure that the new roof system can be supported.

B. Determine fastener requirements.

Choose fastener diameter based on expected minimum pull out results.

Fastener strength should meet or exceed load requirements.

Fasteners should be supplied with long-life coatings or be of stainless steel material for added corrosion protection.

Contact your local fastener supplier or RRA for assistance in defining the proper mechanical, physical and material properties.

C. Installation Hints.

Locate existing wood structure and prepare roof surface to accept the base design of the new framing system.

Apply sealant between existing roof and the underside of framing bottom members.

Install fasteners so that a minimum of 1” of embedment is achieved.

Cover fastener with sealant to prevent leaks.

The temporary waterproofing of an existing roof during the installation of a retrofit rood is of greatest importance. The following guidelines are RRA's suggestions, but these suggestions in no way override good construction practices and onsite requirements.
(Connections of the framing system to the existing structure typically are to be designed and provided by others.)

1. Remove all existing gravel and debris from the top of the existing roof at the location where the new bottom member (BM) is to be installed.

2. If holes into the existing roof are to be predrilled, use a BM for a drilling template (If Speaker Plates (SP) are to be used, use the SP instead of the BM for a template). Before lifting the BM or SP after the holes have been drilled, mark the member's location, then lift the member and clean off any debris from the drilling. Apply roofing sealant over the predrilled holes, covering at least 4" around each hole.
3. If self-drilling fasteners are to be used and no holes are predrilled, apply roofing sealant to the existing roof at least 4" past the new BM or SP's approximate attachment location.
4. Apply roofing sealant around all bottom edges and the bottom of the BM or SP and between the BM & SP.
5. Position the BM or SP and install the proper fasteners. After the fasteners are installed adequately cover the heads of all fasteners that penetrate the existing roof and all other penetrations with sealant.
6. The installed should assure themselves through their own analysis that the waterproofing method is adequate. RRA is not responsible for water tightness.

1. Remove all existing gravel and debris from the top of the existing roof at the location where the new bottom member (CBM/CD) is to be installed.

2. Consideration should be given to the fact that the existing roof may not be completely flat, but the new CBM/CD is. When fasteners are installed they may lift the existing roof if the connection is in a low area thus causing a temporary leak potential. It is suggested that the bottom member run be "spudded" if needed.
3. Consideration should be given to the fact that CBM/CD's can cause a temporary dam and openings or gaps should be provided in the CBM/CD's runs.
4. If selfdrilling fasteners are to be used and no holes are predrilled, apply roofing sealant to the existing roof at least 4" past the edge of the new CDM/CD's attachment location.
5. Apply roofing sealant around all bottom edges and continuously along the bottom of the CBM/CD.
6. Position the CBM/CD and install the proper fasteners. After the fasteners are installed adequately cover the heads of all fasteners that penetrate the existing roof and all other penetrations with sealant.
7. The installer should assure themselves through their own analysis that the waterproofing method is adequate. RRA is not responsible for watertightness.