c-port commerical roofing ductwork HVAC new product recycled rubber rubber sustainable

How to Support Ducts On A Rooftop

So you made the decision to run your ductwork on the rooftop, now what?

Field Fabricated Supports

In many cases, non-engineered fabricated supports are built based on immediate need instead of long term performance. When supports are built on site, there can be factors that are overlooked. It is not uncommon for the weight distribution to be overlooked or improperly calculated. Improper support design can cause damage to the roof membrane, roof structure and interior assets. These are a few of the reasons as to why you should consider an engineered support and why it will give you your best chance at a long and damage free roof.  

Some Factors To Consider:

1. Adjustability On Width And Height– Can your duct support be modified quickly to reduce labor time?

2. Spacing– Are you supporting round ducts or rectangular ducts? Typically this will factor into the amount of supports needed and the distance between them.

3. Bases– What type of base will your duct support have? Should you use penetrating or non-penetrating support bases?

The material that the bases are made of will need to be able to withstand the climate. Weather, heat, cold, rainfall and potentially corrosive environments all can be a factor. You will want to ensure whatever support you use will withstand the necessary length of time. Wood, plastic and rubber are all options for the base of the supports. However, wood deteriorates which is why it’s being used less and less. It is too risky to have it deteriorating and pressing into the roof membrane. 

Plastic can also have some limitations when it comes to climate. Sitting in direct sunlight, throughout cold winters takes a toll on the material. You will likely want your duct supports to last the length of the roof. 20-30 years is a long time for a piece of plastic to not break down.

DS & DSW Series


The DS & DSW series is designed to provide support for ductwork. The crossbeam has the ability to be moved up or down on the vertical supports to accommodate varying heights.The bases feature an 8-hole wing fitting for added stability. Our patented C-Port wide-body bases are used with the DSW series.

The DS & DSW series are perfect for situations where the ductwork widths are consistent but the height may vary (as it often does). 

DSA & DSAW Series


The DSA & DSAW Series are also designed to support ductwork. The differentiating feature with this series compared to the DS & DSW is that it features a telescopic crossbeam which allows for 

maximum adjustability. The telescopic crossbeam (which comes in 3 different sizes) can be quickly adjusted on site for a perfect fit.

The DSA & DSAW Series do not come with the upright strut. Since heights are very often changing on a rooftop, we supply all the hardware and fittings to attach the bases to the uprights as well as the crossbeam. The telescopic crossbeam accommodates any 1 5/8″ x 1 5/8″ strut which is readily available to most contractors. The strut can be cut to any height and installed in about a minute. 

One last feature to point out is the swivel fitting that connects the uprights to the bases. It allows the contractor to support ductwork on a sloped and low pitch roof. Equipped with a bolt through the strut, you can secure the angle with a quick tightening of the nut. 

The DSA/DSAW is great for all the other applications that the DS/DSW Series might miss. It provides maximum adjustability on width (and height). When you work with Clearline Technologies, you will get the best support – both in terms of product and service. All of our product lines can be customized, and extra bases can be added for extra stability and a higher load rating. We can also add other features like Slipsheets & extra crossbeams for multiple ducts and lines. Contact us for a free quote at 1-866-444-0009 or

membrane new product recycled rubber roof repair roofing rubber sustainable TPO

TPO to TPO: How to Hand Weld

As always, check with your TPO manufacturer before starting any heat welding as each manufacture may have different chemical compositions which make up the TPO membrane.

This is a step by step tutorial on how to hand weld TPO to TPO. The purpose is to explain this process so a contractor could accomplish this to install our patented CGW with a TPO slipsheet.

What You Will Need:

  • Professional Heat Welding Gun
  • 20 mm or 40 mm nozzle for heat gun
  • Seam Roller
  • Gloves
  • Safety Glasses

Whether you’re doing a sealed seam, flashing or attached a slipsheet, you are going to want to achieve a weld between 1″-1.5″. 
Hand welding involves two stages: A pre-weld and a finish weld.

The Pre-Weld

The first weld you’re going to start with will be the pre-weld. For the pre-weld, you are going to start by placing your nozzle between the two TPO membranes at a 90 degree angle. The nozzle has a slim end which opens up to a wider fitting. You will likely want to place the nozzle under the top layer just past that angle change on the pre-weld (see photo to the right).

heat gun heat weld

Start at one end and work towards yourself. You want to give a little room between the nozzle end and the seam roller, as you do not want to “pinch” the heat. As you begin to weld by heating the membrane, always use the seam roller at a 90 degree angle to the heat gun. Slowly but consistently work your way down the seam rolling over both layers with steady pressure on the seam roller with long steady strokes till you reach the end of the seam or area you are welding. The purpose of the pre-weld is to create an air dam down the seam, to trap the air and heat to enable a good second/finish weld.

PRO TIP: While you weld, make sure to keep you gun as flat as possible so you are blowing the heat into both membranes AND towards the roller. If you angle the gun too much, you will be heating the bottom membrane more than the top and you won’t be blowing the heat towards the seam roller.

The Finish Weld

Start at the same point as the pre-weld, however this time place the nozzle between the membranes at a 45 degree angle up against the pre-weld. This weld will go a little quicker than the pre-weld. Using long consistent stokes, repeat the same process. Getting the hang of the timing will come. You want to ensure that you go at a speed that isn’t too quick where you are not creating that bond, but you also want to avoid over heating the TPO causing “bleed out” from the outer edge. 

PRO TIP: When using the seam roller, ensure that you are rolling with the flat part of the roller and not the edges. Using the edge of the seam roller has been referred to as “stitching” and can create an inconsistent weld which can trap air bubbles. This was common practice in the past, however it may not be the best way to achieve a long lasting weld.

If you are a visual person, The guys at GAF Roofing have a fantastic video that shows this whole process. You can view it HERE.