Building Owners

Roof Hugger has become the re-roofing sub-purlin system of choice by Private and Military Design Professionals, Roof Consultants, Contractors and Facility Managers throughout the Nation.



Roof Hugger was the first low profile notched sub-purlin system in the market back in the early 90’s. With several patents and over 100 million s.f. later, we continue to lead the industry with innovative metal over metal retrofit design.

Roof Huggers pass the WIND TEST!

Engineering and Testing is the key to the success of our retrofit system.  In addition to passing the Wind Test, Roof Huggers also add strengthening benefits to the new metal roof system.

  • No need to remove old roof at high cost, business interruption and possible weather damage.
  • Saves up to 70% of labor on preparation of old roof.
  • Requires only standard tools and fasteners.
  • Precision punched notches act as continuous template.
  • 10′ lengths, 16 gauge, 50 ksi steel.
  • Punched pilot holes for rapid fastening into existing support structurals.
  • Unique “nesting” into old panel profile achieves rugged – stable – low silhouette connection system.
  • Maintains integrity of original design loadings.
  • Achieves “thermal break” air space between old and new roof sheets.
  • Allows for optional insulation.
  • Laboratory and load tested – Certified load charts.
  • Florida product approval on selected assemblies.


  • Uplift and Dead Load Tested
  • Can add Strength to Existing Purlins
  • All Code Required Framing is on Top of Existing Roof
  • No Need to add Purlins inside Building

Checkout our article in Metal Architecture:  Testing Confirms Significant Secondary Benefit of Using Innovative Sub-Purlin System to Facilitate Adding New Metal Roofs Over the Top of Old

Hugger Applications

Initially developed for re-roofing existing metal buildings and metal roofing, some of the Roof Hugger products are also used very effectively in installations over conventional roofing materials in sloped applications. For new construction applications where an air-space cavity is necessary between a new metal roof and a sub-deck for energy efficient and solar thermal systems, Huggers can accommodate the needed airflow.

These are the most common Hugger profiles for adaptation to an existing metal roof.  If your project includes a profile not seen here, all is needed are the physical dimensions of the existing roof.

Because of the manner Huggers are manufactured, they can match virtually any known metal roof profile.  As you can see from the profiles on the preceding page, the most common are ribbed panels with varying rib spacing and standing seam systems (SSR) with varying seam spacing.

For Corrugated type panels, our Corru-Fit™ sub-framing product as shown above is a special system that takes the issues related to these roof’s inconsistent corrugation spacing.  For more information on this product, please refer to Corru-Fit’s Design Guide on our website.

Since 1991, we have maintained a library of published and hand drawn obsolete metal roof profiles that include their physical dimensions, rib spacing and other critical information.  Having this allows us in many cases to verify the existing roof profile you are trying to identify, ensuring the new Roof Huggers are manufactured to “Nest” over the existing roof and its major ribs providing a low-profile sub-purlin system.  Today, in addition to the design community Roof Hugger has become the re-roofing sub-purlin system of choice by many major metal building manufacturers.

With Roof Hugger’s custom fabrication capability, it is typically not a problem to accommodate these.

  • A&S
  • AEP-Span
  • American Buildings
  • Behlen
  • Braden
  • Butler Manufacturing
  • Chief Buildings
  • Cuckler Building Systems
  • Dean Steel Buildings
  • Delta Buildings
  • Gulf States Manufacturing


  • Inland Buildings
  • Kirby Buildings
  • Ludwig Buildings
  • MBCI
  • McElroy Metal
  • Mes-Tex Buildnigs
  • Metallic Buildings
  • Metal Sales
  • Mesco Buildings
  • Midwest
  • Mitchell Buildings (CECO)
  • Nucor Building Systems
  • Pascoe
  • Ruffing Buildings
  • Soule’
  • Steelox-Armco
  • Star Buildings
  • Stran Buildings
  • Vic-West
  • United Structures of AMerica
  • Varco Pruden Buildings
  • Whirlwind Buildings

Today, Roof Hugger has become the re-roofing sub-purlin system of choice by Private and Military Design Professionals, Roof Consultants, Contractors and Facility Managers throughout the Nation.


There are a number of ways that existing metal roofs have been and still are being retrofitted. Many of these methods cannot be considered structurally correct systems. They lack the ability to withstand wind uplift or new drift loads for snow and are subject to failure. Our systems have withstood hurricane force wind loads from Katrina, Ike, Michael and others without a single failure. Roof Hugger has the most tested retrofit assemblies in the market today, using several different new and existing roof panel combinations for testing. It is this testing that ensures our systems are safe and structurally correct. Competitive systems frequently use calculated values without testing confirmation. Roof Hugger sub-framing systems have been installed on over 90 million square feet of existing metal roofs and continue to be installed on approximately 6 million additional square feet annually. This is the primary reason why Roof Hugger is the most specified metal-over-metal sub-framing systems by building owners, federal and state governments, the military and School Boards. Below are some frequently used methods and a list of their shortcomings:

Because of the width of the hat section, only one screw can be installed into the existing purlin. The other screw is attached to the existing 26 to 29 gauge metal, which does not provide sufficient pull-out strength.

Sitting on top of the existing ribs requires a long attachment screw and when exposed to thermal movement, they will “rock” back and forth causing fastener back out and ultimate failure.

Roof Huggers provide a positive connection directly to the existing purlins made available by our factory punched and nesting design.

For the same reasons as #1

Quantity of fasteners for the new metal roof must be increased due to the much reduced pull-out strength into wood, increasing installation labor and material costs.

Pressure treated wood is corrosive when placed in contact with existing and new metal roofs.

If 18 – 22-gauge hat sections are used in lieu of wood, as shown in the above isometric view, these members have a low pull-out strength, reducing system capacity. When used with 16-gauge or heavier, high strength members, the system is still not suitable for through fastened (screw-down) metal roof as they are too rigid for long panel runs to allow for expansion and contraction.

Roof Huggers are made from minimum 16-gauge, grade 50 steel and are Zee shaped, allowing for expansion and contraction like the existing purlins.

Frequently it is necessary to reduce the purlin/clip spacing in the corners and edges of the existing roof to meet current codes. Stand-off clips systems are challenged to withstand the increased wind loads in these zones and often must add purlins under the existing roof to provide the correct clip spacing.

Roof Huggers can be designed with additional sub-framing attached on top of the existing roof, specifically engineered to reduce the existing purlin spacing and properly support the new panels to meet the new wind/snow load requirements.

Most coatings are quick fixes that fail to permanently fix the existing roof.

Preparation of the existing roof is vital to the coating’s adhesion and performance.

They do nothing to comply with new stringent Building Code wind speeds or snow loads and may hide deficiencies.

Roof Huggers provide you with a way to attach a new metal roof with a 50-plus year service life that can meet all current code requirements.

Read more about coatings:

TPO systems have become popular recently since they are slightly less expensive than Metal over Metal Systems.

Design and attachment is critical however. In order to meet existing wind loads the TPO must be connected to the existing purlins per the manufacturers approved and tested details. Systems that are attached only to the existing roof panels, will not comply with the codes.

TPO systems must not allow water to accumulate on the roof surface or overloading and potential collapse is possible (see photo).

TPO systems do nothing to add strength to the existing roof to meet the new code requirements for snow drifting they just add weight.

TPO systems have about half the life span of metal roofing systems, making their slight initial cost advantage a very poor investment.

Roof Huggers provide you with a base for a new long-life metal roof that can comply with all new wind and snow loads. Huggers also create a cavity that can be used to add insulation for increasing the buildings energy efficiency.

Read more about TPO systems:

Roof Hugger sub-purlins are specifically designed to fit over any existing metal roof system.

They are much faster, less complex and less expensive than removing and replacing an old metal roof.

They can be made to a specific height for adding insulation or removing steps in roofs that have created poor weather tight roof connections.

They can add strength to the existing purlins to overcome the additional weight of the retrofit.

They can be designed to allow the new roof to comply with todays stricter building code requirements.

Roof Hugger is the most tested retrofit sub-framing System available. They are made from high strength 16ga. (0.060 min.), 50 ksi, G-90 Galvanized steel.

They will allow an existing screw-down metal roof to be upgraded to a standing seam roof without a major engineering analysis and upgrading the existing purlin bracing to make up for the removal of the diaphragm strength provided by the old roof panels.

Roof Hugger products are made in the USA