Westman Steel: Installation Guide

The following is a basic step-by-step guide for the installation of Westman Steel’s steel roofing and siding.

STEP 1: Material Checklist

It is necessary to make sure all pieces are on hand before starting.

Please stage your material according to roofing, side walls, end walls, sliding door sheets, trims and fasteners, and put them in a convenient location nearest to their application point.

Make sure to use the correct length of sheet in the correct area and be careful to stage, or secure, sheets prior to installation from the elements, and wind, at all times. Please see storage recommendations attached.

Depending on your application, some trims need to be installed before cladding, so to avoid delays please make ensure you have what you need.

STEP 2: Install Roof Trim, Flashing and Westman Steel Underlayment

The examples of trims and fashings used in this guide are only representative of the products available, and may not be recommended in certain applications. Please call us for advice, or direction, as needed.

While the use of trims/fashings are needed to ensure a weathertight building, some trims are optional and can be used to enhance appearance. The following installation instructions refer to fashings and trims that are either, in- stalled before the cladding (Before applied), or installed after the cladding (After applied).

Determine which type you have purchased and follow the appropriate installation procedure.

(a) Gable Trim (Before applied):
To install gable trim, fit the pieces in place, fastening through (at 36” spacing maximum) both top and bottom nail- ing fanges. If this type of trim is used, it is important to properly seal (sealer tape is commonly used) and fasten the cladding sheet along the gable to prevent water from migrating under the sheet and into the building.

(b) Eave Trim (Before applied):
Eave trim are installed before the roof sheets.
There the Eave trim will cover wall sheeting, determine the wall panel depth (e.g. 3/4”) and fasten the top nailing fange of eave trim to allow a space for the wall panels plus a 1/8” clearance. Use at least three fasteners per 10’6” length of trim.

(c) Corner and Ridge Boxes (if required):
Corner and ridge boxes are optional items and are installed after the eave and gable trims are in place. Follow the manufacturer’s directions.

(d) Dormer and Valley Flashings:
Where required, install the valley fashings as shown. It is important that the valley fashing be supported by sheathing or blocking along its entire length. Without this support the fashing will not lie fat and it will be impossible to make a weathertight seal between the roof sheet and the fashing.

The size and shape of valley fashings differ from one roof to another. A low-pitch roof may require a 36” wide valley fashing, whereas a higher-pitch roof may only require one 24” wide. The roofing sheets should be cut at an angle to accommodate the pitch of the valley. A ”W” valley is more effective in channeling water off the roof than a ”V” type. Care needs to be taken to close off the cladding ribs to prevent water backing up under the sheet.

Flashing where the dormer meets the main roof area can be done using Westman Steel Roof Shield, which is an EPDM dormer cap designed for this application (shown as an On-Site Flashing below). Installation details for this can be found at the back of this Installation Guide. The dormer ridge cap needs to be cut and fitted under the main roof sheets.

(e) Membrane:
When sheet steel roofing is installed over a sheathing material such as plywood, it is common practice in some regions, and some applications, to install a synthetic underlayment, or a peel and stick membrane over portions of the roof area. Please consult with your Westman Steel representative for recommendations.

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STEP 3: Roof Sheets

(a) The first thing is to check the roof squareness. At the corner where an eave and gable meet, measure eight feet along the eave purlin and mark. Then measure six feet up the gable edge from the eave and make another mark. Measure the distance between the two marks. If it is exactly ten feet, you have a square roof at that corner. Check all roof corners using this procedure.

NOTE: The following instructions assume that the roof is square. If the roof is not square there are two correction methods that can be used depending upon the severity. If the deviation is not too signiicant, it can be corrected a little sheet by sheet taking advantage of the tolerances in the sheet side laps. For unsquared roofs, the sheet along the gable can be trimmed along its length to match. An After applied gable flashing is used to reduce the visual impact of the trimmed sheet.

(b) Identify the proper seam lap and the proper screw placement to fasten the sheets to the building.

NOTE: When walking on a roof, avoid walking on the ribs. Step where the purlins are and follow the fasteners up or across.

(c) To get the roof sheets up on the roof, put a board or ladder against the fascia board and slope to ground as far away from the building as possible. Using vise grips and a rope, pull sheets up the board and onto the roof. This method is not suited to long sheets.

NOTE: Extra care needs to be taken on windy days to prevent the sheet from buckling or getting out of hand. Work safely.

(d) Start at the eave on the end of the building farthest away from the prevailing winds. Extend the sheet about 1” over gable edge and 1” to 2” over the eave.

(e) Overlap sheet ends by at least 6”. Sheet end overlaps should only be made at a purlin for support. Lay sheets one by one from eave to ridge before commencing second row (below). Do not fasten open side before starting next row. Except for large buildings, a single sheet will span from eave to ridge without requiring overlaps.

(f) Check sheet alignment every four to five rows by chalking a line square to the eave.

(g) Leave the required space at the ridge to accommodate ventilation requirements.

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STEP 4: Install Ridge Cap

There are a number of ridge cap and venting options. When venting, enough space must be left at the top of the roof sheeting allowing a sufficient opening as specified by the manufacturer.

(a) Chalk location of ridge cap on both sides of roof.

(b) Install closure strips/vented closure strips depending on application along chalk line with adhesive.

(c) Place ridge cap, or vents/vented ridge cap, on top and fasten through top of cladding rib and through closure strip. For vents/vented ridge cap, please make sure that closures do not block any drainage holes.

(d) For standard ridge cap, caulk overlapping portion and place next ridge cap on top, repeating the above steps.

(e) For vents and vented ridge cap, they should be fastened through the ribs of the roof sheets and a generous bead of caulking must be applied between the ridge cover and the vent end fanges. ) For a ridge longer than the length of a single vent (normally 10 feet) butt two vents together with the connector fange underneath at the joint. Both vent and end panels fit between the two tabs on the connector fange. End panels are used when vents are installed individually.

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STEP 5: Gable Trim (After applied)

Certain Gable trim are installed after the roof sheets have been installed. If you are using this type of trim, it should be installed as per details attached.

STEP 6: Install Base Flashing

(a) Measure side wall sheeting length and add 1” to determine location of base fashing.

(b) Measure nailing fange of base fashing.

(c) Subtract (b) from (a).

(d) Using the measurement found in (c), chalk a line around the building.

(e) Install base fashing, matching the top of the nailing fange to the chalk line. Using fasteners every 24”, fasten trim.

STEP 7: Other Wall Trims and Flashings

Depending upon the type of building, there are a number of other fashings and trims needed to close off around the various wall penetrations such as doors and windows. The following describes some of the more common types as shown in the details following. Here again, some wall fashings and trims are installed before the wall cladding while others are installed after the cladding. Make sure you know which type you are using.

(a) Inside Corner: available for before and after applied applications.

(b) Outside Corner: available for before and after applied applications. Other options may be available. Please inquire.

(c) Gable Divider: Installed after the end wall siding, but before the gable siding. A gable divider is not needed if the end wall sheets are cut to fit the slope of the roof.

(d) Jamb Flashing: Jamb fashing is used around door openings and installed before the wall siding.

(e) J Trim: Finishing around a door, trimming windows, or being used as a termination strip on wall panels, J trim can be used in a multitude of different applications.

(f) Drip Flashing: Can be used over doors and windows, or as a base and header trim.

STEP 8: Wall Sheeting

Install the side wall and end wall sheeting, beginning on the side opposite primary view, usually the rear wall of the building. This will produce the best appearance since the sheeting laps will be out of immediate view.

(a) Inside Corner: available for before and after applied applications.

(b) Identify the proper seam lap and the proper screw placement to fasten the sheets to the building.

(c) Begin placing sheeting on the side wall at the corner. It is very important to use a level to plumb the wall sheets before fastening.

(d) Check seam lap to ensure a snug fit.

(e) Run the first two fasteners through the girt to hold the sheet in place.

(f) Finish fastening the wall sheets using the proper screw placement, ensuring that the sheets are square and laid evenly.

(g) Continue to fasten the wall sheets around the building, finishing with the gable ends.

STEP 9: Caulking and Clean-up

(a) Caulk around windows and doors for that professional look.

(b) After the cladding sheets are installed, take a soft bristle broom and sweep the sheets to remove any steel shavings or other dirt.

(c) Steel particles left on the cladding will rust very quickly, often staining the paint finish, giving the impression that the roof sheet has rusted.

(d) Dirt left on the sheets will hold moisture and accelerate the deterioration of the paint system

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