Table 5-1. Typical Code: Allowable Re-Roofs Over Existing Roofing

UFC 3-110-03

26 September 2006

5-2.1.1

Recovering Steep Roofing. Re-covering steep roofing such as

asphalt shingles is easily done. Building codes permit either one or two direct

recovers with missing shingles replaced first and curled shingles flattened. No

more than one layer of re-cover roofing may be specified on Military buildings. In

recover, new metal flashing is required.

Generally, underlayment is not required in shingle re-covers. Wood shakes and

shingles are not a suitable substrate for new shingles or shakes and must be

removed.

Table 5-1. Typical Code: Allowable Re-Roofs Over Existing Roofing*

New Overlay Roofing

Existing

Built-Up

Asphalt

Metal

Modified

Roofing

Shake

Shingle

Tile Roof

Roof

Bitumen

SPF

Slate

NP

Built-Up

Yes

NP

Yes (1:6)

Yes

(2.5:12)

Asphalt

NP

Yes

NP

Shingle1

(2.5:12)

Yes2

Asphalt

NP

Yes

NP

shingle Over

Wood

Asphalt

NP

Yes

NP

shingle Over

Asphalt

shingle

Tile Roof

NP

Metal Roof

NP

Yes

NP

Yes

Modified

Yes

NP

Yes

Bitumen

(2.5:12)

* See Chapter 3 for Military limitations on roofing types.

NP = Not Permitted

(X:X) = (Minimum Roof Slope)

1

See specific requirements

2

Board and batten leveling system must be fire stopped

4

Type 30 nonperforated (30 lb.) felt underlayment required for re-roofing.

5-2.2

Recovering Low Slope Roofing.

5-2.2.1

Analysis of Existing System. Recovering of an existing roof is

not allowed without a detailed analysis of the existing roof deck, roof insulation

and the roof structure. This analysis shall include non-destructive moisture

testing, core sampling and a review of the structure by a licensed structural

engineer. See NRCA Manual for additional information. The appropriate

authority must approve recovering of an existing roof.

5-2.2.2

Slope. In existing construction, every effort must be made to

achieve the :12 slope required for new construction. However, where :12

slopes cannot be achieved, :12 may be used with specific approval by the

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