Architectural Roofing Specifications
National Slate Association

Echeguren Slate

Textural Slate Roofs

The term "Textural" is applied to slate roofs in this publication for the first time, so far as is known. It has been here coined to designate those charming roofs of slate which cannot be classified as strictly Standard or Graduated but which range between the two and produce a distinctive and altogether individual result.
The Textural roof presents most facinating possibilities to the designer, for it may be varied in almost hundreds of ways to conform and harmonize with the structure of which it is to become a part. It may be made nearly as chaste as the Standard or it may be almost elaborate as the Graduated. For example, the slates may be uniform in length but vary in thickness, or the thickness may be kept uniform and the length (and exposure) varied. The width may vary or be uniform. Very rough surfaced slates may be introduced into an otherwise almost smooth roof. The slate may be laid with varying exposure or the butts may be chipped and broken at irregular angles. When the thickness is varied the usual range is from 3/16" to 3/8" but if a heavier and more irregular effect is desired, this may be accomplished by incorporating certain percentages of thicker slates.
These present only a few of the opportunities for interesting treatment. In addition, the color of the slates may be used with splendid effect by mixing slates of different tones, but the tone value or predominating color effect desired should always be specified. When color is used, accidental or "freak" slates may be introduced throughout the roof, adding greatly to the picturesque effect of the ensemble.
The cost of a textural roof will depend entirely upon the effects desired, and although usually slightly greater than the Standard roof, will not equal in material or labor the cost of a Graduated roof.
The various details of construction, sheathing, ridges, hips, valleys, flashings, etc., shown in connection with the Standard slate roof apply also to the Textural roof. The construction may require additional collar beams, supports or slightly heavier rafters than for a Standard roof, depending upon local conditions and construction as well as the weight of the roof selected.

STANDARD SPECIFICATIONS FOR A TEXTURAL SLATE ROOF

NOTES

1. This specification used as here given will provide for a complete slate roof as follows:

Felt- Saturated Asphalt commercially known as 30 lbs. per sq.
Flashings- 16 oz. copper.
Slate- 3/16" to 3/8", random width, approved lengths.
Valleys- Closed.
Hips- Saddle.
Cement- Elastic Waterproof.
Ridges- Saddle.
Nails- Copper.

2. The following must be written into the specification under paragraph:

3-c Slate- Predominating color.

3. It should be noted that metal work is not covered by this specification, as seperate Standard Specification for Sheet Metal Work are given on page 48. The specifications for Slate Roofing and sheet metal work are so arranged, however, that they may be handled seperately or together to conform to variation in custom in different sections of the country.

4.See also General Notes- All Specifications, Page 48.

SHORT FORM SPECIFICATION

Note: In using the Short Form if any optional paragraphs are desired so state.

1. SLATE ROOFING

(a) Furnish all materials and labor and cover with slate portions of the building shown, marked or indicated for slate, and form all slate hips and ridges in accordance with the Specification "T" for a Textural Slate Roof, 1925, of the National Slate Association, 791 Drexel Building, Philadelphia, Pa.

(b) The predominating color of the slate shall be ____________________________.

2. SHEET METAL WORK

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STANDARD SPECIFICATION "T"

(Covering in detail all materials and labor in connection with a Textural Slate Roof.)

1. General and Guarantee

(a) The General Conditions of the contract are hereby made a part of the contract and this contractor shall examine these General Conditions and thoroughly acquaint himself with all the requirements therein contained.
(b) This contractor shall furnish all material and labor in accordance with the drawings and these specifications.
(c) The roofing contractor shall furnish samples of the slate he proposes to use. If required, a layout shall be prepared by the producer and submitted to the Architect for approval.
(d) This contractor shall inspect all surfaces prepared for slating by other trades, point out to the proper authority all defects, and shall not proceed with the laying of felt, flashings or slate until the necessary corrections have been made.
(e) Roofing shall be applied by workmen experienced in the applying of slate.
(f) The roofing contractor shall furnish his own scaffold or rigging, or arrange with the general contractor for the use of scaffolds furnished by others.
(g) A written guarantee shall be furnished that the materials are in strict accordance with these specifications and the samples submitted, and that any and all repairs required on the roof due to defective materials or workmanship furnished under this contract shall be made without cost to the owner, for a period of one year.

2. Roofing Felt

(a) On all boarding to be covered with slate, furnish and lay asphalt saturated rag felt, not less in weight than that commercially known as "30 pound" felt.
(b) Felt shall be laid in horizontal layers with joints lapped toward eaves and at ends at least 2" and well secured along laps and at ends as necessary to properly hold the felt in place and protect the stucture until covered by the slate. All felt shall be preserved unbroken, tight and whole.
(c) The felt shall lap over all hips and ridges.
(d) Felt shall be lapped 2" over the metal of any valleys or built-in gutters.

3. Slate

(a) Slate shall be in combinations of thicknesses from 3/8" to 3/16" thick.
(b) Slates shall be of random widths and of such lengths as approved by Architect.

(c) The predominating color shall be ___________________________________.

(d) All slate shall be hard, dense, sound rock, machine punched for two nails each. No cracked slate shall be used. All exposed corners shall be practically full. No broken corners on covered ends which sacrifice nailing strength or the laying of a watertight roof will be allowed. No broken or cracked slates shall be used.

4. Hips

(a) All hips shall be laid to form "Saddle" Hips without metal underneath.

5. Ridges

(a) All ridges shall be laid to form "Saddle" Ridges. The nails of the combing slate shall pass through the joints of the slates below.

6. Valleys

(a) All valleys shall be laid to form "Closed" Valleys.

7. Elastic Cement

(a) Cement shall be an approved brand of waterproof elastic slaters' cement colored to match as nearly as possible the general color of the slate.

8. Nails

(a) All slate shall be fastened with large-head slaters' copper nails of sufficient lengths to adequately penetrate roof boarding. Care shall be taken to avoid exposing the nails on cornice, soffits, overhanging eaves, etc.

9. Slating

(a) The entire surface of all main and porch roofs, the roofs and sides of any dormer windows, if shown, and all other surfaces so indicated on the drawings, shall be covered with slate in a proper and watertight manner.
(b) The slate shall project 2" at the eaves and 1" at all gable ends, and shall be laid in horizontal courses with the standard 3" headlap and each course shall break joints with the preceeding one. Slates at the eaves or cornice line shall be doubled and canted by a wooden cant strip.
(c) Slates overlapping sheet metal work shall have the nails so placed as to avoid puncturing the sheet metal. Exposed nails shall be permissible only in top courses where unavoidable.
(d) Neatly fit slate around any pipes, ventilators, etc.
(e) Nails shall not be driven in so far as to produce a strain on the slate.
(f) Cover all exposed nail heads with elastic cement. Hip slates and ridge slates shall be laid in elastic cement spread thickly over unexposed surface of under courses of slate, nailed securely in place and pointed with elastic cement.
(g) Build in and place all flashing pieces furnished by the sheet metal contractor and co-operate with him in doing work of flashing.
(h) On completion all slate must be sound, whole and clean, and the roof shall be left in every respect tight and neat example of workmanship.

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For further information, or to order the complete Slate Roofs Handbook from the National Slate Association, contact:

Echeguren Slate, Inc.
1495 Illinois St.
San Francisco, CA 94107

(415) 206-9343

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e-mail : slate@echeguren.com