Sheet Metal Worker Red Seal metal roofing, cladding and specialty products practice questions (308A).

Five free practice questions on metal roofing, cladding and specialty products: block D of the Red Seal 308A Sheet Metal Worker exam, about 10 of its 120 questions. They are in the exam's format: four options, one correct answer. Answer each one before opening the explanation. No account, no email.

01The questions

1. Procedural · Installs non-stainless steel specialty products

   PVC-coated steel duct has been set on supports in a trench and will be encased in concrete. What must be done before the concrete is placed?

   1. Place all the concrete in one lift to even out the pressure.
   2. Wrap it in polyethylene so the concrete does not bond to it.
   3. Seal the joints from inside after the concrete has set.
   4. Strap the duct down to anchors so it cannot float.
   Show the answer

   D. Correct. An empty duct displaces far more than its own weight of wet concrete, so it rises (floats) as the concrete is placed unless it is held down. It is strapped to anchors at the spacing the drawings give before the pour, and the concrete is placed in lifts where the drawings call for it.

   Why not the others

   A. One deep lift puts the full uplift on the duct at once and makes flotation more likely. The duct is anchored down, and the concrete is placed in lifts as the drawings or engineer direct.

   B. A wrap does nothing to hold the duct down; the empty duct is buoyant in wet concrete and floats out of position. Strap it down to anchors before the pour.

   C. Wet concrete and water can enter unsealed joints during the pour, and the duct will still float. Joints are sealed before placement, and the duct is strapped down so it cannot rise.

   Source: Red Seal Occupational Standard, sub-task D-17.02

2. Recall · Installs roofing and cladding/siding system components

   An architect is concerned about oil canning, the visible waviness in the flat pans of a new standing seam wall. Which panel feature helps reduce it?

   1. A wider flat pan, so there are fewer seams pulling on it.
   2. Striations or pencil ribs rolled into the pan's flat.
   3. A thinner sheet that flexes evenly across the pan.
   4. Exposed screws through the middle of each pan.
   Show the answer

   B. Correct. Shallow striations or pencil ribs stiffen the flat and break up the reflection, so small waves in the metal are much less visible. Heavier sheet, narrower pans, a flat substrate and clips that let the panel move also help.

   Why not the others

   A. A wider flat is less stiff and shows waviness more, not less. Narrower pans, or striations or pencil ribs in the flat, are what reduce oil canning.

   C. Thinner metal is less stiff and more prone to oil canning. A heavier sheet, narrower pans or ribs rolled into the flat reduce it.

   D. Screws through the middle of the pan pin it so it cannot move with temperature, which adds stress and waviness, and they put exposed holes in a concealed-fastener system. The flat is stiffened with striations or pencil ribs instead.

   Source: Red Seal Occupational Standard, sub-task D-15.03

3. Recall · Fastens exterior components

   A polycarbonate sign face is to be sealed into its aluminum frame. Besides weather resistance, which property of the sealant matters most?

   1. Colour match to the frame, which hides the joint line.
   2. Compatibility with the plastic, which some sealants craze.
   3. Fast cure, which lets the face be handled sooner.
   4. Hardness when cured, which locks the face rigidly in place.
   Show the answer

   B. Correct. Solvents or cure by-products in some sealants attack polycarbonate and cause fine surface cracks (crazing) that spread and cloud the face. Use a sealant that the plastic's or the sealant's maker lists as compatible with polycarbonate.

   Why not the others

   A. Colour is a matter of appearance; a sealant that matches the frame but attacks the plastic will still craze the face. Compatibility with polycarbonate decides the choice.

   C. Cure speed is a convenience. A sealant that cures fast but is incompatible with polycarbonate will still craze the face, so compatibility comes first.

   D. Polycarbonate expands and contracts much more than the aluminum frame, so a hard, rigid bead stresses the face; the sealant needs to stay flexible and, above all, be compatible with the plastic.

   Source: Red Seal Occupational Standard, sub-task D-16.02

4. Recall · Installs stainless steel specialty products

   A thin stainless panel bows as two workers carry it, then springs back flat when it is set down. A sharp knock against a column, though, leaves a permanent dent. Which property let the panel spring back flat?

   1. Malleability.
   2. Ductility.
   3. Elasticity.
   4. Hardness.
   Show the answer

   C. Correct. Elasticity is a metal's ability to return to its original shape when a load is removed, as long as the load stays below the point where the metal yields. The knock went past that point, so the dent is permanent (plastic) deformation.

   Why not the others

   A. Malleability is the ability to be permanently shaped by hammering, rolling or pressing without cracking. Returning to the original shape after the load comes off is elasticity.

   B. Ductility is the ability to be stretched or drawn out without breaking, which matters when metal is permanently formed. Springing back to the original shape is elasticity.

   D. Hardness is resistance to indentation, scratching and wear; it bears on how easily the knock dented the panel, not on why the panel sprang back after flexing. That is elasticity.

   Source: Red Seal Occupational Standard, sub-task D-17.01

5. Procedural · Seals exposed joints

   Flat-seam copper pans will be soldered on a low-slope dormer roof. At what stage are the edges of the pans tinned?

   1. After the pans are cleated down, just ahead of the iron.
   2. After the seams are malleted flat, along the exposed edge only.
   3. Before the edges are folded and the pans locked together.
   4. Only where seams cross, once the rest is soldered.
   Show the answer

   C. Correct. Tinning both faces of each edge before it is folded puts a coat of solder inside the lock, where the iron cannot reach later. When the seam is sweated, that solder melts and joins the solder fed at the edge, so the lock fills right through instead of being sealed only at its face.

   Why not the others

   A. By the time the pans are cleated down and locked, the faces inside the lock are closed off. Tinning is done on the flat edges before folding so solder is already inside the seam.

   B. Once the lock is folded and flattened its inside faces can no longer be tinned, and solder run only along the edge can seal the face of the seam while leaving the inside of the lock dry. The edges are tinned before they are folded.

   D. Every seam needs its edges tinned, not just the crossings, and it has to be done before folding. Tinning the crossings after soldering the field leaves the rest of the locks with no solder inside them.

   Source: Red Seal Occupational Standard, sub-task D-15.04

02Answer key

03What block D covers

Work on the building envelope and on specialty installations: laying out metal roofs and walls, underlayment and isolation materials, standing seam and exposed-fastener panels, copings, ridge caps and flashings, sealing joints, steel deck, awnings and signs on exterior walls, and installing stainless steel kitchen and laboratory products, copper and zinc panels, PVC-coated and plastic duct, and lead shielding.

The Red Seal Occupational Standard names this block “Installs roofing and specialty products”. It carries 8.3% of the exam, about 10 of the 120 questions, split across three tasks. The share column is each task's weight within the block, as the standard publishes it.

04What the questions turn on

Plan around seams and wind

Round penetrations go in the flat of a pan, clear of the seams on both sides so the flashing base lies flat. Exposed-fastener panels start at the downwind end, so the side-lap edges face away from the prevailing wind.

Isolate the metal, let it move

Aluminum built into mortar gets bituminous paint on every contact face, because alkaline moisture attacks it. On a copper roof, rosin paper over asphalt felt keeps the pans from sticking, so they can slide on their cleats.

Work slopes out with trigonometry

A 7 in 12 slope is the inverse tangent of 7 over 12, about 30.26 degrees, so ridge cap legs meet at 180 degrees less twice that, 119.5 degrees. A panel along a slope is the hypotenuse of its run and drop.

Check gauge and alloy, then report

Stainless, galvanized and aluminum each have their own gauge table, so the same gauge number is not the same thickness. Type 430 delivered where Type 304 is drawn is held unused and reported, since substitution is the designer's decision.

05The other blocks

The 308A exam has five blocks. Each has its own page of free questions:

The 308A Sheet Metal Worker practice exam page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.