Aluminum Glazing Extrusions


for enhanced view click the images
Colorado aluminum glazing systems, aluminum glazing, aluminum glazing system, pro-seal aluminum glazing system, roof glazing system

Designing with Pro-Seal


There are two categories for glazing applications….

  • Vertical and Sloped = walls and roof

The type of cap bar used for each assembly application is the only difference. For vertical applications such as exterior walls. Think of it as a picture frame design with 45-degree angle joints on each outer corner joining 2 vertical end sides of the perimeter.

  •  When glazing a structural wall from end to end with post, evenly spaced, select the Perimeter assembly for the top, bottom and end sides of the entire end to end wall.
  • When glazing / joining 2 sheets of polycarbonate or 2 panes of glass between 2 evenly spaced posts or rafters, always use the Mullion assembly, the mullion assembly uses the same cap as the perimeter assembly.
  • The Bevel Purlin assembly, for most roof applications, is placed horizontally on top of the purlin support members.
  • For sloped roof applications use the same Base Perimeter assembly for top / sides and bottom. At the bottom end of the roof perimeter use the Bevel Perimeter assembly. The base bar for each assembly is the same. The only difference is the cap.


The Perimeter assembly uses a flat cap and the Bevel perimeter assembly uses a bevel cap as noted in the design picture.

The Perimeter bar and Mullion bar (base bars) screw directly to the support structure. This could be wood or steel …the attaching framing member must have a 3” wide surface since the width for all Perimeter assemblies is 2-13/16” wide and 3-1/8” wide for vertical mullion assemblies.

After installing glass or polycarbonate panels, the glazing and bevel cap screws into the base assembly bars.

As a rule, the perimeter base bars run continuously across the top, with 45-degree angle joints at the top 2 corners. The vertical mullion base bars butt into the inside of the top perimeter bar. The bottom perimeter base and bevel cap goes between the width of each bay. The perimeter base situates between the vertical mullion bars. As noted in the design picture.


  • Perimeter Assembly
  • Mullion Assembly
  • Purlin Assembly

The perimeter assembly is the only assembly available in 3 different heights to accommodate 3 different thicknesses of glazing material, glass or polycarbonate.

1” – 5/8” – 1/4 “GLAZING THICKNESS

The mullion and purlin assembly accommodates all 3 glazing thicknesses; the only difference is the length of the attaching screws.Whenever there are 2 or more rows of glazing on a sloped roof from top to bottom (ridge to eave) The Purlin base and bevel cap divides the rows horizontally.
Trim back 1/4″ – 1/2″ the outer legs of the purlin base bar, which overlaps the outer edge of the mullion bar.

See illustration of the mullion vertical bar for weeping purposes.

The EDPM glazing rubber should extend pass the glazing bar so it snugly touches the perimeter rubber. Rubber tends to shrink a bit when exposed to constant sunlight. Best to cut a bit long and snug.



The Pro Seal glazing system designed to be placed on top of structural support framework. Such as, glue-lams (wood) or steel rectangular tubes which are designed to support snow and wind loads for your local building codes.

Suitable types of wood construction are laminated rafters and posts, (glue-lams) 3×6-8 rafters, headers, 3×3 post, or double 2x framing, or nailing 1x to each side of a 2x. The end result is to have a 3” wide surface to attach the aluminum glazing assemblies securely.


Exposed by design, should always be stained and sealed with 2 coats of sealer before construction, as this will provide a very long lasting and beautiful looking structure without deteriorating from harmful UV exposure.


Do not come with pre-drilled attaching holes… therefore, do predrilling before installation. Best to start 3-6” inches from either end of the base bar and start an even hole layout.


Drill clean through the center screw track on all assembly base bars with a 7/32” drill bit every 15 – 18” apart (minimum), start hole layout 2” from either end. Label the top of each bar according to layout destination.

For assembly cap bars use 9/32” drill bit and drill holes every 12-16” apart, start hole layout 1” from either end of the cap bar. Just make sure to not drill holes so that the attaching cap screw does not hit or interferes with the top hex head of the attaching base screw, since both screws will go directly into the same center screw track.


The bottom run of the perimeter base bar must have 2 drilled out weep holes with 3/16” drill bit for each glazed bay. Hold the perimeter bar on edge and drill 2 holes clean through, starting on the bottom surface the outside leg / through the screw track race / and clean through the gasket race.

Measure 4-6” in from each end of the horizontal perimeter bar. Attach setting block closest to the corner and away from the weep holes. Do not locate holes under the setting blocks.


All glazing units, whether its single glass, double pane glass or polycarbonate, must be 1-1/4″ smaller than the actual length and width, best to measure center to center dimensions of the base center screw track.

The glazing unit must rest fully flat on the EDPM glazing rubbers edge, closets to the center screw track. For best results, measure every bay individually, record and label each measurement from the outer edge of the glazing EDPM rubber.

From side to side (across) and from the setting block up to the top edge of the glazing rubber. This is a sure way to know that all glazing panels will fit perfectly.


as a rule, when assembly base bars are predetermined to an approximate length, its best to install the glazing EDPM rubber before cutting to final sizing and before installation.

Cut the rubber gasket 1” – 4” or so beyond the length of the assembly bars. When installing each of the assembly bars trim rubber even and accordingly to the final length with sharp utility blade, or use miter saw with carbide tipped blade.

To facilitate sliding the rubber through the rubber track with longer length assembly bars, spray soapy warm water on the rubber track as well as the rubber itself.  Soapy warm water acts a lubricant and works just fine. Sometimes, if needed, it’s best to push the rubber down into the track so that it seats properly… If the screw track gets dirt inside the track, dry and blow the dirt or sand particles out, before installing the rubber gasket.


Aluminum extrusions can best be cut with a power miter saw with sharp carbide tooth blade. Be sure to support and brace extrusions securely while cutting.


When installing the purlin bars on a roof slope.They must overlap the vertical mullion by about a 1/4 “(see   illustration) …the outer legs cut back about 1/4″ – 1/2 “from each end. Notch it down to the bottom surface of the base purlin bar and break off… best to file the notched surface clean from any burrs, then install.


must be used in conjunction with any aluminum glazing system (see illustration). Flashing at the top, bottom, and sides. Flashing requirements, are specific to each project and highly recommended for a leak proof installation. The supporting structure will determine how flashing profiles will have to be custom bent for a nice clean fit. Flashing details must be anticipated and installed before final installation of all assembly base bars…


follow these recommended procedures. At the bottom, of any roof slope, run sill flashing continuously under the bottom perimeter bar assembly and under the vertical mullion assembly. Be sure to overlap across 4 – 6” with silicone caulk under the overlap on all continuous flashing runs.

At the top, run continuous flashing over the top of the perimeter glazing cap and crease downward towards the edge of the glazing. Ridge flashing or ridge cap should go over the top bar flashing run. This will provide a leak proof double layer of flashing.

On the sides, its best to clamp continuous flashing runs between the perimeter base bar and the perimeter glazing cap. This flashing run should be bent and over the rake at the outer edge of the rafter bar or end of structure.

Aluminum glazing extrusions is the best way to glaze any wood framed structure.


When framing with aluminum glazing extrusions, for a glazed sloped roof, all top surfaces of each roof framing member must be on the same plane and flush with each other. Check to make sure that every opening is true and square. Install pre-bent flashing before securing the glazing system perimeter bars and mullion bars.

Assembly base bars are attached with #10 x 2” attaching screws, comes with system.

Always start with installing the top perimeter bars first. Use a string line from end to end of the structure frame. Make sure top perimeter bar is even and equally distant to the top corners of the structure frame. Caulk the back side of the top perimeter bar and where needed. Next install the left and right side base bars making sure the sides are square with the frame and the top perimeter bar. The top 2 corners should be mitered with a 45-degree miter joints, caulk the 45-degree splice.


install the vertical mullion bars onto the top of the rafters, butt the top of each mullion bar to the inside top of the perimeter bar.  Align the bottom of the mullion bar even with the lower perimeter bar. Next… cut and install the bottom perimeter bar. Position each lower perimeter bar in between each mullion bar. (see illustration)


Install the purlin base bars, turn the bar up and fill the screw holes with clear silicone caulk. Turn the bar back right side up and place mullion bar with legs down on the purlin support frame member. Position the purlin bars between the mullion bars. With the notched ends on both sides to overlap onto the gutter edge of the mullion bar.

The overlap should be about 1/8” or 1/4” into the mullion bar. Pull the rubber gasket beyond the bar so it touches the mullion rubber gasket…


the glazing should lay flat and should evenly encompass the full width. From the setting block to the outside edge of the glazing rubber. Once it is glazed, begin installing the glazing caps to secure the glazing. The holes for the screw cap should be pre-drilled and ready to accept the glazing cap screws. Use 7/16 nut driver for the hex head.


caulk all the butt joints and miter joints before installing the trim covers. Recommend cleaning the joints with isopropyl alcohol before caulking this makes for a better seal.

Now that you come this far,  and when it begins to get overwhelming,….and it will. Take a break, and start a new day.

Our latest in depth and informative blog post is available!