Wood shingle roof, Metal roof-over, worn out (C) Daniel Friedman Guide to Re-roofing with Wood Roof Shingles & Shakes
     


InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Roof-over with wood shingles or shakes: this article discusses re-roofing over other materials using wood roof shingles and shakes. We describe installing wood shingles or shakes over asphalt shingles, or installing new wood shingles or shakes over existing wood shingles or shakes. We list manufacturers & product sources for wood shingle or shake roofing.

Green links show where you are. © Copyright 2015 InspectApedia.com, All Rights Reserved.

Re roofing With Wood Shakes or Wood Shingles?

Wood shingle roof past end of life (C) D FriedmanOur page top photo shows a wood shingle roof on the historic Mesier Homestead in Wappingers Falls, NY. Or wood roof photo at left illustrates a wood shingle roof that is past end of useful life. This roof needs replacement.

[Click to enlarge any image]

Can we roof-over this surface with new wood shingles or does the roof need to be stripped off?

Adapted/paraphrased with permission from Best Practices Guide to Residential Construction, chapter on BEST ROOFING PRACTICES:

Under some conditions, shakes and shingles can be installed over existing roofing, as follows:

Advice for Installing Wood Shingles or Shakes Over Existing Asphalt Shingles

If the existing asphalt shingles are not overly cupped or deteriorated, split or rough-sawn shakes can be installed over the shingles using interlaid strips of felt, as described above. Installing wood shingles over asphalt, however, requires a ventilating underlayment such as Cedar Breather or a system of battens (as shown in Figure 2-47 and Figure 2-48).

Figure 2-46: Wood Roof Shakes Installed over Spaced Sheathing (C) J Wiley, S Bliss

Figure 2-48 below. [Click any figure or table to see a larger, more detailed version.]

Figure 2-46: Wood Roof Shingle installation detail (C) J Wiley, S Bliss

Advice for Installing Wood Shingles or Shakes Over Existing Wood Shingles

Curled wood shingle roof - early failure (C) D FriedmanOur wood shingle roof photo at left raises some interesting questions about both the original wood shingle installation and now the question of roof replacement.

The shingles do not look worn compared with our worn-out wood shingle photo shown earlier in this article. But the shingles are badly curled and many are splitting, risking leaks. The roof seems to be failing earlier than one might have expected.

We recommend diagnosing the cause of this problem before re-roofing. Is this wood shingle curling and splitting due to:

  • A poor quality wood shingle? (click to enlarge this or any image at InspectAPedia)
  • Improper or inadequate under-roof ventilation? While some roofing standards permit installation of wood shingles over solid plywood decking, where we [DJF] have inspected such installations we've seen wood roof shingle failures occurring in less than 10 years.
  • Other improper installation details?

A second question is whether or not it would be reasonable to roof-over this existing surface. Without diagnosing the ventilation question first one might hesitate in any case to roof over this surface, but roofing over badly curled roof shingles on an existing roof is asking for trouble. The new roof may itself be unable to lie flat and the uneven underlying surface may contribute to early splits in the new wood shingles or shakes.

If the shingles are not badly curled or deteriorated, they can form an adequate surface for new shingles or shakes.

Watch out: Do not place building felt under the new shingles as that could inhibit drying, but if there is a high risk of decay (moist environment, low slope, overhanging trees), a layer of Cedar Breather is recommended. Shakes should be installed in the normal fashion with interlaid felt. Use nails long enough to penetrate the sheathing.

Advice for Installing Wood Shingles or Shakes Over Existing Shakes

In most cases, these will need to be removed before re roofing, as the surface is too irregular, and nailing through the shakes into solid sheathing is impractical.

More Information about Wood Shingle or Shake Roofing Materials, Methods, Standards

  • Cedar Shake and Shingle Bureau www.cedarbureau.org

-- Adapted with permission from Best Practices Guide to Residential Construction.

Advice for Replacing Individual Lost or Damaged Wood Shakes or Shingles

Slate roof repair method for installing individfual slates without having to do a tear-off (C) Daniel FriedmanReader Question 6/23/14 Kevin P. said:

Lets say that you have a condition in which a storm event has resulted in a handful of broken and/or partially displaced wood shakes on the roof.

What would be the best strategy for replacement of those individual shakes?

Can they easily be spot replaced, or would it require a sequence of events, including a large area of removed shakes either above or below the damaged shake?

Reply:

Kevin, an experienced roofer who is familiar with wood shake roofs can replace or repair missing or loose shakes in spots without removing large areas of materials.

S/he might have to work from a ridge-hooked and padded ladder on some fragile roofs that can't be walked-on without risking further damage, but key in any event is the use of repair methods similar to that for repairing slates - another non-flexible roof material that doesn't allow you to just "lift up" an upper shingle course to nail a lower shingle in place.

You'll see that using a slate hook or even a simple strip of copper (see our sketch at above left) can allow us to hold new slates (or shakes) in place when just a few spots need repair - a much less invasive and much less costly approach.

See SLATE ROOF REPAIRS for examples of these individual shake or slate replacement methods.

 

Continue reading at WOOD ROOF COATINGS & FIRE RATINGS or select a topic from the More Reading links shown below.

Suggested citation for this web page

WOOD SHINGLES, RE-ROOFING WITH at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

More Reading

Green link shows where you are in this article series.

...




Frequently Asked Questions (FAQs) about re-roofing with wood shingles or shakes

...

Ask a Question or Search InspectApedia

Questions & answers or comments about roofing over an existing roof using wood shingles or shakes.

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

HTML Comment Box is loading comments...

Technical Reviewers & References

Publisher's Google+ Page by Daniel Friedman

Click to Show or Hide Citations & References