ASC Building Products

Table of Contents
Section	Page(s)
Introduction	1
Minimum Recommended Tools & Equipment	2
Delivery, Handling and Storage	3
Safety Considerations	3
Panel Profile and Description	4
Map of Typical Conditions	5
Fasteners	6
New Siding Preparation	7-9
Re-Siding Preparation	10-11
Inside Corner Flashing	12
Step Flashing	13
Window/Door Flashings	14-15

Panel Installation	16-18
Panel Endlap	19
Outside Corner Flashing	20
Window Flashing Finish	21
Top of Wall Finish Flashing	22
Top of Wall/Gable Flashing	23
Mounting Light Base Flashings	24
Final Instructions	25
Clean-Up
Repair
Maintenance
Electrical Grounding
Standard Flashings	26

TriLap® Steel Siding Installation • February 2024

ASC Building Products

Introduction
TriLap® is a horizontal steel siding panel for use in new or retrofit construction. The 3-lap panel profile available in custom, long lengths is designed with ease of installation as a primary consideration. The fol- lowing guide is intended to help the installer achieve a high level of quality in the finished product. Please do not hesitate to contact your ASC Building Products representative with any questions you might have.

Manufacturing Location:
Anchorage
2441 Cinnabar Loop
Anchorage, Alaska 99507
800-478-2727
907-349-2727

Important Notice
Be sure to read this manual in its entirety before begin- ning installation.

This manual is provided to the customers of ASC Building Products as a guide to assist in the installation of TriLap® Steel Siding. Use for any other
purpose is prohibited. This manual remains the prop- erty of ASC Building Products.

ASC Building Products assumes no responsibility for any problems which might arise as a result of improper installation or any personal injury or proper- ty damage that may occur with the product’s use.

Note: Each flashing part in this guide has been assigned a part number, Each part number contains one or two letters followed by one or two numbers, for example: (WA21). These part numbers have been provided for you to make ordering these flashing parts quick and easy.

TriLap® Steel Siding Installation • February 2024 1

2	February 2024 • ASC Building Products

Trilap® Steel Siding
Installation, Flashings and Details Guide

Minimum Recommended Tools & Equipment
Screw Gun: Clutch type screw gun with depth locating nose piece allowing variable torque settings is recommended to insure proper installation of the screws. 1/4" hex head driver will be required.

Snips: For miscellaneous panel and flashing cutting requirements. Three pairs will be required for left edge, right edge and centerline cuts.

Electrical Metal Shears: Used for general metal cutting, such as at endlaps, doors and windows.

Note: Some erectors prefer to use circular power saws with metal cutting abrasive blades. While the use of power saws may be faster, there are some disadvantages that must be considered: 1) The edges of metal that have been saw cut are jagged and unsightly, and are more likely to rust than sheared edges; 2) Saw cutting will leave small particles of metal on the panel surface that will rust and dam- age the panel finish if not completely removed. ASC Building Products does not recommend this method.

Panel Shear: A field shear the shape of the panel, used to make square end cuts at the jobsite.

Chalk line: Used to assist in the alignment of panels and flashings.

Caulking Gun: For miscellaneous caulking and sealing.

Rivet Tool: Used for miscellaneous flashing and trim applications.

Marking Tools: Indelible markers, pencils, or scratching tools.

Scratch $wl: Can be made from old screw drivers ground to a point. Used to mark the steel, open hems and as a punch.

Utility Knife: Used for miscellaneous cutting.

Electric 'rill: Used to drill holes such as those required for rivet installation.

String line: Used for general alignment and measuring.

Tape Measure: 25 foot minimum (another 50 ft. is handy).

locking Pliers: Standard and “Duckbill” style for miscella- neous clamping and bending of parts.

+aPPer: Used with nails to fasten flashings.

2 June 2002

Trilap Steel Siding Installation Guide • February 2024	3

ASC Building Products

Delivery, Handling and Storage

Always check the shipment upon delivery. Check for damage and check material quantities against the shipping list. Note any damaged material or short- ages at the time of delivery and notify your supplier within 24 hours.

Handle panel bundles and individual panels with care to avoid damage. Longer bundles and panels may require two or more “pick points” properly spaced to avoid damage that can result from buck- ling and/or bending of the panels. Request a copy of the Long Length Handling Instructions and diagrams from your supplier as required.

Store the panels and other materials in a dry, well ventilated area and away from traffic. Elevate one end of the bundle, maximum 2'-0", so that any moisture that may have accumulated during ship- ping can run off. Be sure that air will be able to cir- culate freely around the bundles to avoid the build- up of moisture. Never store materials in direct con- tact with the ground.

Some products may have a peel off plastic coating over the painted surface. This coating was factory- applied to prevent damage to the finish that may occur during manufacturing or shipping. If this coat- ing is present, avoid exposure of the “peel-coated” parts to sunlight and remove the “peel-coat” prior to installation.

Safety Considerations

Always wear proper clothing and safety attire.
Wear proper clothing when working with sheet metal in order to minimize the potential for cuts, abrasions, and other injuries.

Use care when operating electrical and other power equip- ment.
Observe all manufacturer’s safety recommendations.

Siding installation on windy or stormy days can be danger- ous.
Avoid working with sheet metal products on windy or stormy days.

TriLap® Steel Siding Installation • June 2002 3

4	February 2024 • ASC Building Products

Trilap® Steel Siding

Installation, Flashings and Details Guide

TriLap® Steel Siding

4 June 2002

16"
3A1E/ COVERAGE

Concealed fastened, 16" wide, 3-lap panel profile.

Custom long lengths for easy installation.
29 gauge painted panels readily available. (Inquire about 26 gauge and 24 gauge availability.)
Factory-notched for quick installation.
Rich cedar embossed wood grain appearance.
Alaska produced.
Coil coating offers good surface hardness as well as excellent flexibility for woodgrain embossing.
Top coat is specially formulated to resist abrasion, metal marking, and staining
Requires minimal maintenance.
Matching flashings and accessories.
Optional weep holes.

Note: Weep holes are not recommended unless project condi- tions require. Call an ASC Building Products representative for more information.

Trilap Steel Siding Installation Guide • February 2024	5

ASC Building Products

Map of Typical Conditions

MOUNTING LIGHT BASE WINDOW / DOOR
TOP OF WALL GABLE TOP OF WALL FINISH STAGGER PANEL ENDLAP
INSIDE CORNER

STRAIGHT PANEL ENDLAP BASE FLASHING
OUTSIDE CORNER

STEP FLASHING

TriLap® Steel Siding Installation • June 2002 5

6	February 2024 • ASC Building Products

Trilap® Steel Siding

Installation, Flashings and Details Guide

Fastener Selection

Fastener #	Description	Use	

1	7d Galvanized Box Nail
Not furnished by ASC Building Products	Wall angle, corner bracket undersill flashing, finish flashing at top of wall or gable and base flashing	

2	No. 10 - 15 HWH Woodscrew
available in 1", 1 1/2", 2", 2 1/2"
and 3"	Panel-to-wall substrate attachments, Starter Strip	

3	STST-42 Stainless Steel Rivet 1/8 x 1/8"	Flashing-to-flashing attachments (lapped joints such as outside corners)	

4	No. 10 x 3/4" Stitch Screw	Flashing-to-flashing attachment	

Proper Installation of Gasketed Fasteners	

Correctly	
	Driven	
	
Under	
	Driven	
	
Over	
 		Driven	

Notes:
The table above shows the fasteners required for TriLap® Steel Siding. Refer to the panel installation and flashing details of this manual for specific screw and nail usage and spacing.
Panel attachment screws must be long enough to fully penetrate through the structural sheathing, or penetrated solid lumber at least one inch.
All screws and nails must be coated to provide protection against corrosion.
Exposed fasteners should have sealing washers and be the same color as the parts they attach.
Note: Screws and nails must be properly driven to ensure proper seal, holding strength, and allowance for expansion and contraction. Over driven fasteners may restrict panel from expanding and contracting properly, and may cause buckling or oil canning of the panel. Correctly driven fasteners will have a very slight gap between the panel surface and the washer base.

6 June 2002

Trilap Steel Siding Installation Guide • February 2024	7

ASC Building Products

New Siding Preparation
ASC Building Products TriLap® Steel Siding can be used in both new construction and re-siding applica- tions. We recommend horizontal installation of TriLap® Steel Siding over a rated structural sheathing.
However, application over intermittent supports with rigid insulation is possible. Contact ASC Building Products for additional information.
New Siding:
Make sure there are no nails or other objects pro- truding from the substrate that might puncture the air barrier or the wall panels.
Check all details for possible wall penetrations which must be added to the substrate prior to wall panel installation.

Cover the entire wall section with an air infiltration barrier. Install horizontally. (See illustration No. 1)
Begin at the base and roll out the air infiltration bar- rier horizontally. Allow each consecutive section to overlap the previous section a minimum of 3". Overlap the end laps a minimum of 6" when start- ing a new roll of air infiltration barrier.
Areas of air infiltration barrier that have been torn or cut should be replaced or repaired prior to installa- tion of the metal siding.

Continued next page

ILLUSTRATION NO. 1

6" END LAP

3" SIDE LAP

AIR INFILTRATION BARRIER

FOUNDATION FACE

TriLap® Steel Siding Installation • June 2002 7

8	February 2024 • ASC Building Products

TriLap® Steel Siding
Installation, Flashings and Details Guide

New Siding Preparation continued
The following steps need to be taken prior to installa- tion of wall panels.
Complete installation of air infiltration barrier as shown on page 7.
Starting at the corner, attach the Base flashing (B21) with nails at 12" o.c. Allow for a 1" overlap on the foundation face.
Check each side of the building to determine the lowest point from which the siding is started. Measure up from this lowest point, the width of the Starter Strip (SS21), as a base point for your chalk line. Stretch the chalk line to a corner sighting along the line to make sure it is level and straight.

Snap the line to provide a reference mark for the Starter Strip (SS21). Repeat on remaining sides of the building making sure that the line meets on all corners. Hold the Starter Strip (SS21) back 4" from each corner. (See illustration No. 2)

Note: The Starter Strip (SS21) must be straight, level, and line up at all corners since it will determine the line of all the siding panels.

Fasten Starter Strip (SS21) through the structural sheathing to engage the wood or steel studs. Maximum 12" o.c. attachment.

Continued next page

ILLUSTRATION NO. 2

1"

3"

2"

821

SS21

4"

STARTER STRIP (SS21)

1.  7d BOX NAIL @ 12" O.C.

BASE FLASHING (B21)

1" OVERLAP

FOUNDATION FACE

8 June 2002

Trilap Steel Siding Installation Guide • February 2024	9

ASC Building Products

New Siding Preparation continued
Place Wall Angel (WA21) plumb 1 1/2" maximum from the corner, flush with the foundation at the bottom, and nail at 12" o.c. along the flange against the wall.

Next, proceed to the opposite end of the wall and attach another Wall Angle (WA21) as noted in step 5.
Proceed to pages 12 - 16 for additional flashing details applicable to installation.

ILLUSTRATION NO. 3

2"

1 1/2" FROM THE CORNER

3/4"

WA21

1.	7d BOX NAIL @ 12" O.C.

1 1/2" FROM THE CORNER

WALL ANGLE (WA21)

STARTER STRIP (SS21)
BASE FLASHING (B21) FOUNDATION FACE

TriLap® Steel Siding Installation • June 2002 9

10	February 2024 • ASC Building Products

ASC Building Products

Panel Installation
Procedure (continued)
Panel is secured over Starter Strip (SS21) and is posi- tioned at each and inside the Wall Angle (WA21).
Fasten the panel through the pre-punched slots at 12" o.c. maximum.
Follow guidelines for fastening on page 6 to ensure proper attachment.

Continued next page
2"

2"

3/4"
SS21	WA21

ILLUSTRATION NO. 7

12" O.C. MAXIMUM ATTACHMENT

WALL ANGLE (WA21)

TRILAP WALL PANEL

STARTER STRIP (SS21)

TriLap® Steel Siding Installation • June 2002 17
Trilap Steel Siding Installation Guide • February 2024	11

ASC 8uilding Products

Re-Siding Preparation continued
Install the Base Flashing (B21), starting at the cor- ner. Attach at 12" o.c. with nails, allowing 1" to overhang onto the foundation face.
Install the Starter Strip (SS21) with fasteners attached to vertical wood furring. Follow align- ment instructions on page 8.

Place Wall Angle (WA21) 1 1/2" from corner, flush with the foundation at the bottom, and nail 12"
o.c. along the flange against the wall.
Proceed to pages 12 - 16 for additional flashing details applicable to installation.

WA21	2"

3/4"

12" O.c. MAXIMUM

SS21
2"

821

3"

1 1/2"

EXISTING SIDING

BASE FLASHING (B21)

STARTER STRIP (SS21) FOUNDATION FAcE
WALL ANGLE (WA21)

TriLap® Steel Siding Installation • June 2002 11

12	February 2024 • ASC Building Products

Trilap® Steel Siding

Installation, Flashings and Details Guide

Inside Corner Flashing

2"

2 1/2"
7/8"

1 1/4"

SS21	C22

STARTER STRIP (SS21)

1.

5"
7d BOX NAIL @ 12" O.C.

CONTINUOUS BEAD OF GUNNABLE SEALANT

C-METAL (C22)

3rRFedXreV
Air infiltration barrier not shown.

12 June 2002

Install first C-metal (C22) approximately 1/2" from wall, aligning bottom edge with bottom edge of siding. Attach 12" o.c. with nail.

Apply a continuous bead of gunnable sealant or mastic to back edge of installed c-metal.
Install second C-metal (C22) as shown; attach every 12" o.c. with nail.

Trilap Steel Siding Installation Guide • February 2024	13

ASC 8uilding Products

Step Flashing

3 1/2"

2"

2 1/2"

3"

	 7/8"
US21	SS21	821

TRILAP WALL PANEL

1.	7d BOX NAIL @ 12" O.C.

UNDERSILL FLASHING (US21)

FOUNDATION STEP

STARTER STRIP (SS21) BASE FLASHING (B21)

FOUNDATION FACE

3URFHGXUHV
Air filtration barrier not shown.
Install Starter Strip (SS21) and Base Flashing (B21) as instructed on page 8.
Install Undersill Flashing (US21) on upper area.
Measure and cut panel so fit is snug in the Undersill Flashing (US21).

14	February 2024 • ASC Building Products

Hook panel over Starter Strip (SS21) and slide into Undersill Flashing (US21).
Fasten panel at the top after it is positioned properly.

TriLap® Steel Siding Installation • June 2002 13

Note: C21 C-metal may be used as a substitute to US21

Trilap® Steel Siding

Installation, Flashings and Details Guide

Window/Door Flashings

C-METAL @ HEAD
1 3/4"

5/8"

7/8"

822 or 823

7/8" @ B22
1 1/4" @ B23

2 1/8 @ C21 (OPTIONAL)

3 1/2"

1 1/4" @ C22

DRIP FLASHING (B22)

C-METAL @ JAMB

C-METAL @ SILL

C21 or C22

3roFHGXrHV
Air infiltration barrier not shown.
The C-Metal (C21 or C22) is manufactured in 10'- 6" pieces. These stock lengths have to be cut
4 1/4" or 2 1/2" longer in length than the width and height of the window. Five (5) pieces per window are required: one Head, two Jambs, one Sill, and one Drip Flashing.
Part #1 (shown in drawing above) requires a piece 7/8" x 2 1/8" or 7/8" x 1 1/4" to be removed from the top end between the paralleled 2 1/8" or 1 1/4" and 3 1/2" legs. Repeat this notch-out at the bottom of Part #1. Prepare the opposite Jamb C-Metal (C21 or C22) in the same fashion.

14 June 2002

Cut a piece of Drip Flashing (B22 or B23) 2" longer than the width of the window (outside to outside of jamb reveals + 2"). For example, using the 1 3/4" x 7/8" x 5/8" Drip Flashing (B22 or B23), make two 1" cuts along the 7/8" leg making a tab to be bent down and over the outside of the notch in the jamb legs at a later time.

Prepare the Head and Sill C-Metals (C21 or C22) by making 2 1/8" or 1 1/4" cuts in the 7/8" leg leav- ing 1/2" or material for a tab to be turned down over the Drip Flashing (B22 or B23) tab, as shown above. Make a clean, straight miter cut creating a “picture frame” corner at each end of the Head and Sill C-Metal (C21 or C22).
Nail the Drip Flashing (B22 or B3) in place fol- lowed by the jamb legs. The Drip Flashing (B22 or B23) measuring 1 1/4" wide is used where the win- dow/door opening is trimmed with brick moulding.
Slide the Head C-Metal (C21 or C22) into place, tak- ing care to position the 3 1/2" leg of the jambs behind the 3 1/2" leg of the heads, and the 2 1/8" leg of the jambs behind the 2 1/8" leg of the heads. The top of the jambs 2 1/8" vertical leg should end inside of the open hem of inside of the Head C-Metal (C21 or C22). Install all four corners in this fashion.
Note: Dimensions on attachment flange may differ from C21 or C22 illustration.

Trilap Steel Siding Installation Guide • February 2024	15

ASC Building Products

Window/Door Flashings

DETAIL A

DETAIL B

C-METAL @ HEAD DRIP FLASHING (B22) C-METAL @ JAMB

DETAIL A

DETAIL B

C-METAL @ JAMB C-METAL @ SILL

TriLap® Steel Siding Installation • June 2002 1

3URFHGXUHV FRQWLQXHG IRUP SDJH 
Fasten the C-Metal (C21 or C22) to the wall with nails at 12" o.c.

5

Measure and cut panels so the fit is snug in the Sill C-Metals (C21 or C22) and Jamb of C-Metal (C21 or C22).

16	February 2024 • ASC Building Products

Note: A full length panel may not be installed around a window. An endlap panel detail at door and window openings may be required. See page 19 for instructions on how to endlap a panel.

Trilap® Steel Siding
Installation, Flashings and Details Guide

Panel Installation
General
Study the details section of this manual prior to the installation of the panels. Pay close attention to the following:
Determine which flashings need to be installed prior to installing the panels. For example, Starter Strip (SS21) and Wall Angle (WA21). See pages 8 and 9 for instructions.
Some panels may require notching or cutting prior to installation., For example, around door and win- dow openings.

Procedure
Align the first panel with the Starter Strip (SS21). Engage the panel over the Starter Strip (SS21) by lifting the panel up until it is firmly locked over the Starter Strip (SS21).
Fasten panel.

Note: Provide proper spacing between panel edge and wall angle (WA21) for expansion or contraction of panel. See page 22.

ILLUSTRATION NO. 6

PANEL LENGTH

2"

SS21

WALL ANGLE (WA21)

STARTER STRIP (SS21)

BASE FLASHING (B21)

16 June 2002

Trilap Steel Siding Installation Guide • February 2024	17

ASC Building Products

Panel Installation
Procedure (continued)
Panel is secured over Starter Strip (SS21) and is posi- tioned at each and inside the Wall Angle (WA21).
Fasten the panel through the pre-punched slots at 12" o.c. maximum.
Follow guidelines for fastening on page 6 to ensure proper attachment.

Continued next page
2"

2"

3/4"
SS21	WA21

ILLUSTRATION NO. 7

12" O.C. MAXIMUM ATTACHMENT

WALL ANGLE (WA21)

TRILAP WALL PANEL

STARTER STRIP (SS21)

TriLap® Steel Siding Installation • June 2002 17

18	February 2024 • ASC Building Products

TriLap® Steel Siding
Installation, Flashings and Details Guide

Panel Installation
3rRFedXre (continued)
Align the second panel bottom edge over the first panel top edge.
Fasten the panel as shown on page 17 and per the guidelines for fasteners on page 6.

Note: As additional panels are installed, make sure the panels are measured and cut properly for door and window openings. If pan- els are lapped end-to-end, see illustration No. 9 on page 19.
During installation, measure both ends of every third panel to ensure they remain level.

Install panels to allow for expansion and contraction as noted on page 22.

ILLUSTRATION NO. 8

18 June 2002

Trilap Steel Siding Installation Guide • February 2024	19

ASC Building Products

Panel Endlap
Panels lapped end-to-end should be overlapped 1".
Note: The panel is factory-notched to accommodate endlaps.

Before lapping panels, place a continuous bead of gunnable grade sealant along the centerline of the endlap. (Chemically cured sealant is
not recommended.)

Join the panel together and fasten as indicated on page 17.
Install one rivet on the bottom side of each board return area.

ILLUSTRATION NO. 9

CONTINUOUS BEAD OF GUNNABLE GRADE SEALANT

3.

STST-42 STAINLESS STEEL RIVET @ BOTTTOM SIDE OF EACH BOARD RETURN AREA

1" PANEL OVERLAP

TriLap® Steel Siding Installation • June 2002 19

20	February 2024 • ASC Building Products

Trilap® Steel Siding

Installation, Flashings and Details Guide

Outside Corner Flashing

2"

15/16"

1 7/16"

/16"

15/1

1 7/16"
15/16"

 3/4"

15

3 1/2"

6"	3 1/2"

WA21	OC25	OC21

OUTSIDE CORNER (OC21)

OUTSIDE CORNER BRACKET (OC25)
7d BOX NAIL @ 12" O.C.

3. 1/8" X 1/8" STAINLESS STEEL RIVET

Top OC21	4"

WALL ANGLE (WA21)

TRILAP WALL PANEL

CUT AND REMOVE THIS MATERIAL

Lower OC21

STARTER STRIP (SS21)

3roFeGXreV
Air infiltration barrier not shown.
Install starter strip and base flashing as instructed on page 8.
Attach Wall Angle (WA21) 1 1/2" from corner as instructed on page 9.
Install Outside Corner Bracket (OC25) abutting the Wall Angle (WA21) as shown above. Attach every 12".

20 June 2002

Snap lock Outside Corner (OC21) over Outside Corner Bracket (OC25) starting at the foundation.

Lap consecutive outside corner flashings 4" with lap joint facing downhill. Remove hem from bot- tom Outside Corner (OC21) before lapping. Rivet each side of the corner through the lap joint.

Note: For applications with a single 10'-0" corner, install a rivet on each side of the corner at the top. The rivet will attach the corner to the Wall Angle (WA21) so it will not slide off.

Trilap Steel Siding Installation Guide • February 2024	21

ASC Building Products

Window Finish Flashing

C-METAL

WINDOW FINISH FLASHING (F22)

7/8"

2 1/2" (C22)
2 7/8" (C21)

1 1/4" (C22)
2 1/8" (C21)

C21 or C22

1 1/4"

2 3/4"

C-METAL

F22

Procedures
Install window finish flashing (F22) in C-Metal (C21 or C22) at sill of long windows.
Fasten 12" o.c.
Insert cut edge of panel in window finish flashing (F22) to secure cut edge.
Note: A wood shime inserted behind window finish flashing (F22) is recommended to prevent oil canning.

TriLap® Steel Siding Installation • June 2002 2

22	February 2024 • ASC Building Products	1

Trilap® Steel Siding

Installation, Flashings and Details Guide

Top of Wall Finish Flashing

CONTINUOUS BEAD OF GUNNABLE GRADE SEALANT

1"

2 7/8"

7d BOX NAIL @ 12" O.C.

#10-15 HWH WOOD SCREW @ 12" O.C.

F21

FINISH FLASHING (F21)

Panel Length	Total Movement
w th 1001: change n temperature	
10'	1/8"	
20'	1/4"	
30'	3/8"	
40'	1/2"	

TRILAP WALL PANEL

2.	#10-15 HWH WOOD SCREW @ 12" O.C.

3rRFedXreV
Air infiltration barrier not shown.
Slide last panel into place. Fasten with #10 fastener at 12" o.c.
Apply a continuous bead of sealant on the under- side of the Finish Flashing (F21)

Attach Finish Flashing (F21) over edge of panel. Nail 12" o.c.

22 June 2002

Trilap Steel Siding Installation Guide • February 2024	23

ASC Building Products

Top of Wall/Gable Flashing

C21

3 1/2"

2 1/8"

7/8"

C-METAL (C21)

1.	7d BOX NAIL @ 12" O.C. CUT TRILAP WALL PANEL
AT AN ANGLE TO SLIDE INTO THE C-METAL

3URFHGXUHV
Air infiltration barrier not shown.
Install C-Metal (C21) along gable. Nail at 12" o.c.
Measure and cut panel at an angle to slide into C-Metal (C21).
Hook panel on previous panel and slide it into the C-Metal (C21).

24	February 2024 • ASC Building Products

Fasten panel with a #10 fastener at 12" o.c. through pre-punched holes.
To fit panel in opposite end, hold outside edge of C-Metal (C21) open to allow panel to slip inside.

TriLap® Steel Siding Installation • June 2002 23

Note: Dimensions on attachment flange may differ from illustration.

Trilap® Steel Siding

Installation, Flashings and Details Guide

Mounting Light Base Flashings

MB21 and MB22

1 5/8"

3/4"

2x8 OR 2x10

MOUNTING LIGHT BASE

7 5/8" @ MB21
9 5/8" @ MB22

3/4"

1.	7d BOX NAIL

SECTION A-A

3rRFedXreV
Air infiltration barrier not shown.
The Mounting Light Base (MB21 and MB22) is designed to provide a flat mounting surface for the wall. This will enable items such as exterior lights and exhaust fan vents to be attached to a surface matching the TriLap® Steel Siding color and texture.
The covers are dimensional to enclose a square piece of wood 2 x 8 (7 5/8" x 7 5/8") or 2 x 10

24 June 2002

(9 5/8" x 9 5/8").

A square piece of 2 x 8 or 2 x 10 is attached to the wall before the Trilap panels are installed. Apply the Mounting Light Base (MB21 or MB22) over the 2 x 8 or 2 x 10, nailing through the attachment legs to hold in place.
Prepare and install flashing similar to window and door flashing on pages 20 and 21, around the perimeter of the Mounting Light Base (MB21 or MB22). Install the TriLap wall panels.

Trilap Steel Siding Installation Guide • February 2024	25

ASC Building Products

Final Instructions
Clean-Up
Inspect panel surfaces and flashings for loose debris and metal shavings.
Remove debris and metal shavings by wiping pan- els down with a soft cloth.
Dirt residue can be removed by washing panels with a mild detergent, water, and soft cloth.

Repair
Severe scratches, dents and holes will require panel replacement.
Small scratches do not require touch-up paint if the scratch does not penetrate the Zincalume® substrate under the paint.
ASC Building Products does not recommend touch-up painting of damaged surfaces (minor
scratches, etc.) due to fading and weathering differ- ences of the touch-up paints in comparison to fac- tory-applied paint systems.

Maintenance
Inspect siding and flashings annually.
Remove debris to ensure panels are moisture free.
Tighten loose fasteners and repair joints that may need new sealant.
If needed, wash panel surface with a mild deter- gent, water, and soft cloth.
Re-painting panels should not be required for the life of the building. If a new color for panels or trim is required, please inquire with ASC Building Products for more information.

Electrical Grounding (if required)
All siding and flashings shall be grounded by attaching a No. 8 hot-dipped galvanized wire to an electrical ground rod with a connector approved by Underwriter’s Laboratories.

TriLap® Steel Siding Installation • June 2002 25

26	February 2024 • ASC Building Products

Trilap® Steel Siding

,QVWDOODWLRQ, )ODVKLQJV DQG 'HWDLOV *XLGH

TriLap Siding Standard Parts

F21	1"	Finish Flashing, painted page 22

2 7/8"

823	1 1/4"	Drip Flashing, painted
page 14
1 3/4"

5/8"

WA21	3/4"	Wall Angle, painted page 9, 11, 17, 20
2"

C22	1 1/4"	C-Metal, painted page 12, 14
7/8"

2 1/2"

F22	2 3/4"	Window Finish, painted page 21

1 1/4"

OC25	15/16" 1 7/16" 15/16"  Outside Corner Bracket, bare
26 gauge
15/16"	page 20

1 7/16"

15/16"

2"

SS21

Starter Strip 26 gauge-Bare page 8, 11, 12, 16, 17

823

1 3/4"

1 1/4"

Drip Flashing, painted page 14

5/8"

3"

%21

Base Flashing, painted page 8, 11

:$2 

3/4"

2"

Wall Angle, painted page 9, 11, 17, 20

1/2"

OC21

3 1/2"

Outside Corner Flashing, painted, page 20

C22

7/8"

1 1/4"

C-Metal, painted page 12, 14

2 1/2"

2 1/8"

7/8"

2 7/8"

3 1/2"

C21

C-Metal Flashing, painted page 14, 23

F22

2 3/4"

1 1/4"

Window Finish, painted page 21

%22

7/8"

 / "

1

5/8"

)21

1"

2 7/8"

US21

3 1/2"
2 1/2"

Drip Flashing, painted page 14

Finish Flashing, painted page 22

Undersill Flashing, painted page 13

2C2 

OC2 

OC27

15/16"

1 7/16"

15/16"

15/16" 1 7/16" 15/16"

Outside Corner Bracket, bare 26 gauge
page 20

Outside Corner Bracket 45°

Outside Corner 45°

7/8"

26 June 2002

Trilap Steel Siding Installation Guide • February 2024	27