Residential Roofing Materials » Wind Uplift

Asphalt roofing shingles:nails and nailing issues(2nd part)

The Roof Buying Team — Sat, 12 Mar 2011 18:18:38 +0000

2nd part

read the 1st part here

HOW MANY NAILS PER SHINGLE?

It depends on the number of tabs.

For example the normal three – tab rectangular asphalt shingles used in USA / Canada need 4 nails: two above the cutouts and two near the edges.

In Europe, mostly four-tab asphalt shingles are used and the number of nails needed is 5/shingles.

More nails are needed:

- in windy regions

- when slopes are very steep, normally bigger than 200%.

In this case two nails are used above the cutout. So 6 nails will be needed for the 3-tab shingles and 8 nails for the 4-tab shingles.

WHAT ABOUT STAPLING ?

Stapling is not recommended in Europe and as far as I know also in USA and in Canada.

Stapling can easily damage shingles.

WHERE EXACTLY TO PLACE THE NAILS?

In Europe we place the nails a little above the sealant strip. The nails are placed 2-3cm above the upper point of the cutout. The nails near the edges should not be closer than 2,5cm from the edges.

On no occasion should the nails be driven into discontinuities and problematic points of the substrate.

HAND NAILING OR PNEUMATIC NAILER?

Hand nailing is more accurate. It does a better job but it is slower and most expensive. If you cannot afford hand nailing for the whole project, at least use it:

- near the rakes

- for the first course at the eaves

- for the ridge and the hips

- for the valleys.

Because hand nailing is more accurate, it will reduce the possibility of wind uplift at this critical regions.

The nails should be driven vertically and flush with the upper side of the asphalt shingle securing it in its position.

If the nail is overdriven, it will harm the integrity of the asphalt shingle.

If the nails are underdriven, they cannot fix / secure the asphalt shingles properly.

In the case that the nails are not completely vertical, they will harm the shingle with their heads. These nails should be discarded and replaced.

CONCLUSION

Learn the right nailing techniques because they are critical for the expected life and behaviour of the shingles.

Do pay to buy the best quality nails in the market.

Chris Strogilis

Civ. Eng. – MBA – DipM

http://maconwaterproofing.blogspot.com/

Civil engineer with postgraduate studies in MBA and Marketing

Article from articlesbase.com

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Asphalt roofing shingles:nails and nailing issues

The Roof Buying Team — Sun, 06 Mar 2011 15:14:42 +0000

If I had to vote for the most important accessory of asphalt shingles, nails would be hands down by preferred choice.

Nails keep the asphalt shingles in their place for many years. They protect them against wind uplift in windy and coastal regions.

Consequently, I would harness my frugal instinct at the time of buying roofing nails.

QUALITY OF NAILS

The best option is hot dipped galvanized nails (dipped in a hot zinc bath). Thus, a zinc oxide coating is formed on the metal surface which works as a sacrificial anode.

Electroplated galvanized nails are generally not recommended to be used with asphalt shingles.

GEOMETRICAL CHARACTERISTICS

Shank diameter:

It should be round 3mm. Barbed shanks are preferable.

Shank length:

It will depend on several factors:

- the existing norms

- the type (thickness) of shingles

- if the project is about new roofing or reroofing over all asphalt shingles

- number of shingle layers

- if nailing is near the ridge area etc.

- the type of the substrate.

Generally in U.S.A. the minimum recommended penetration length is 19mm whereas in Europe the recommendation is more flexible.

The massive quantity of nails used in Europe are 20mm long (25mm for ridges) which means that penetration is normally less than 15mm.

In case that the underside of the deck is visible e.g. in kiosks or pavilions, the manufacturer should be consulted for the idoneous solution.

Nailhead diameter:

This is very critical parameter with regard to wind uplift resistance. A minimum diameter around 9-10mm is recommended.