Roofing, Flashings & Chimneys Flashcards by Kathy Andrews

Two main categories of roofing systems

Sloped Roof (steep roofs) 4 in 12 > and flat roofs (low sloped roof) between 2 in 12 and 4 in 12

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Roof Pitch

ratio of the vertical rise over a set horizontal run(12 ft) so a 6 in 12 is 6 ft vertical rise over 12 ft horizontal run

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Asphalt Shingles

asphalt impregnated felt paper or glass fiber mats, coated with a layer of asphalt and covered with granular material

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Asphalt Shingles - Life expectancy

15, 20, 25, 30 or 35 year - manufacturer’s warranty

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Asphalt Shingles - wear factor

Exposure (sun) and slop (steeper the slope the longer they last)

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Asphalt Shingles - self-sealing shingle

self sealing strip that sticks 2 shingles together to protect shingles from being blown off in heavy winds

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Asphalt Shingles - granular material

protects the shingle from ultra violet light

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Shingles used for roof pitch between 2 in 12 and 4 in 12

conventional asphalt shingles but first cover the roof with non-perforated, asphalt-saturated felt papers or a waterproof membrane

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Re-Roofing asphalt shingles

Can re-roof over one layer but they will perform better and last longer if you remove the old roofing material. Can’t go over 2 layers.

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Difference between wood shingles and shakes

Wood shingles are machine cut and typically smaller, thinner and more uniform and thicker. Wood shakes are hand or mechanically split and have a much more uneven surface.

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Wood shingles - life expectancy

30 to 40 years

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Wood shingles - re-roofing

You can install over a layer of ashpalt shingle but it is better to remove existing shingles to allow wood roof to breathe

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Wood Shingles - How much is exposed to weather

1/3 of the wood

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Slate Roof - life expectancy

200 years

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Slate Roof - Biggest Problem

The nails that hold the slate in place rust and allow the slate to come loose and then water rusts the nails of nearby slates

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Slate Roof - reroofing

Slate roofs should never be installed over another layer of roofing

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Slate Roof - Flashing

Slate roofs generally outlast the flashing and require a section of roof to be replaced

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Concrete Roof Tiles - Replace asphalt

Concrete roof tiles are much heavier than asphalt shingles and may require modifications to the roof structure

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Fiber Cement Shingle - Life Expectancy

30 to 50 years

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Types of Metal Roofs

Copper, Steel, terne and tin

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Metal Roofs and tar

Metal roofs should never be covered with tar because moisture trapped below will cause rust

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Corrugated Plastic Roof usage

Generally used over patios and light structures

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Built-Up Roofing (Tar and gravel)

They are multiply consisting of two to five plies of roofing felts with a coating of asphalt in between layers. A flood coat of asphalt is then applied on top and covered with gravel to reflect ultraviolet light and protect roof from mechanical damage

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Built-Up Roofing - slope

They are designed for flat appilcation with a slope that is no greater than 3 in 12.

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Built-Up Roofing - Life Expectency

two ply roofs - 5 to 10 years, 4 ply roofs 15 to 20 years

Built-Up Roofing - Wear factors

If moisture is trapped below or within membranes, blisters and bubbles form

Build-Up Roofing - Water ponding

water ponding on a short roof life by 50%

Built-Up Roofing - Re-roofing

It is common to install over the top of existing, best practice is to remove old roof first

Build-Up Roofing - Leaks

Because of construction of built-up roofs, leaks are difficult to isolate and repair. Water can travel a significant distance before you see the stain on the ceiling.

Roll Roofing/Selvage Roofing

Comes in typical rolls of 18 or 36 inches

Roll Roofing - Attachment to roof

It is either attached with roofing cement, sealed at the seams or nailed at the edges

Roll Roofing - Life Expectancy

5 to 10 years

Single-ply roofing membranes

thermosets, thermoplastics, and modified bitumens.

Single-ply membranes - common problems

seam, flashing and installation problems

Modified Bitumen Roofing - UV protection

By a coating of granules, foil or paint

Single Ply membranes - Re-roofing

Most plastic and synthetic rubber roof membranes are not compatible with asphalt and should not be installed over built up roofs

General Roofing - Max number of layers of asphalt shingles

two

General Roofing - What 4 areas are vulnerable to leakage

Joints, seams, change in roof direction, things that obstruct the flow of water (chimneys, dormers)

General Roofing - Tree Branches

Tree branches will rub the shingle and damage the roof

General Roofing - Ice damning

Is most common on low sloped roof

General Roofing - 4 - Ice daming solutions

increase attic insulation, increase attic ventilation, seal openings in attic floor and seal/insulate attic heating ducts

General Roofing - How does Ice daming occur

Occurs when snow and ice collect, often at the eaves. Melting snow on the upper portion of the roof, warmed by the attic, cannot drain properly as it is trapped behind the still frozen dam at the cold eaves.

Where are flashing used?

They are used where dissimilar materials meet, where a material changes direction, at roof penetrations and at joints in materials - When a roof line changes direction, a ridge, a valley, or a hip is created.

4 materials used for flashing

Steel, aluminum, lead or copper

Difference between an open and closed valley

An open valley has the metal showing a closed valley has shingles covering it

How many layers of roll roofing can be used in the valley for flashing

two

Best material to use for flashing

Metal

What material is used for hip and ridge flashing on asphalt shingle roofs

flexible shingles

Where the flat roof meets the sloped roof the membrane should extend?

3 feet up the roof

What are the 2 types of roof to wall flashing required when a roof slope is parallel to a wall

Counter flashing and "L" shaped step flashing

On roof//sidewall intersection, how far about the roof surface should wood siding materials be?

2 inch

When is a chimney more likely to leak?

When it is installed at the bottom on the roof versus the peak.

What precautions should be taken when installing high side portion of chimney flashing?

The flashing on the high side should typically extend up at least 6 inches or one-sixth of the width of the chimney whichever is greater

What should be installed over the top of a parapet wall?

Cap flashing

What materials are used for flashing around plumbing stacks?

Metal or rubber flashing

What is a pitch pan?

a sheet metal pan round the stack or mast is filled with pitch or tar to a depth of one to two inches.

A skylight should sit on a curb that protrudes how man inches about the sloped roof surface?

4 inch minimum

What is the purpose of a gravel stop?

securing and protecting the roof membrane at the edge of the roof, preventing the gravel from sliding off the roof, and forming a drip edge to keep water run-off from damaging the wood fasci

Chimneys are constructed of?

Masonry or metal

What is a chimney flue

Separate channel for smoke to the outside

What can share a flue?

2 appliances on the same floor of the house

3 common materials used to line a chimney-flue

Clay tile, metal or asbestos cement pipe

Most common element in chimney deterioration?

Water

What would a ring of accelerated deterioration around the exterior of a masonry chimney indicate to you?

There is a gap in the tile liner of the chimney

Chimney Cap

to protect the top surface of a masonry chimney from water usually concrete

Rain Cap

covers the chimney flue to prevent water from entering the flues

Chimney Bracing

Should be on masonry chimneys that are more than 12 feet above last support and metal chimney's that are over 5 to 6 feet tall

Chimney Height

minimum of 3 feet above the point of penetration through the roof and two feet higher than anything withing 10 feet of them to help ensure good drafts