Survey of Literature on Specifications for Stucco Lath

Publisher’s version / Version de l'éditeur:

Technical Note (National Research Council of Canada. Division of Building Research), 1954-10-01

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.

https://nrc-publications.canada.ca/eng/copyright

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

Questions? Contact the NRC Publications Archive team at

PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.

NRC Publications Archive

Archives des publications du CNRC

For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.

https://doi.org/10.4224/20358605

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at

Survey of Literature on Specifications for Stucco Lath

Tibbetts, D. C.

https://publications-cnrc.canada.ca/fra/droits

L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

NRC Publications Record / Notice d'Archives des publications de CNRC: https://nrc-publications.canada.ca/eng/view/object/?id=44d867a8-81d9-4e01-b34b-8f5317f90b6e https://publications-cnrc.canada.ca/fra/voir/objet/?id=44d867a8-81d9-4e01-b34b-8f5317f90b6e

DIVISION OF BUILDING RESEARCH

NATIONAL RESEARCH COUNCIL OF CANADA

.

,

'f

E

C

1HIN II CAlL

NOTlE

INo.

ｾＸＷ

NOT FOR PUBLICATION

General Distribution

PREPARED BY D.C. Tibbetts PREPARED FOR

CHECKED _BY C. R. C. and \AJ.H.B.

FOR INTERNAL USE

APPROVED BY

ｾ

.:::::::=:----ｾ October, 1954.

SUBJECTSurvey of Literature on Specifications for

Stucco Lath.

This Note contains a listinf of various lathing ｳｰ･｣ｩｦｩ｣｡ｴｩｯｾｳ

to[ctli-.:r '\'ri_{th their recommendations for type of lath and method of}

application. It is thought that it would be useful to have these

specifications grouped together for purposes of comparison and.

reference for use in code work and for ｰｾｯｪ･｣ｴｳ related to the

performance of stucco on various baC'l"-in: ;"

InfDrmation from the following organizations and documents is contained herein:

Metal Lath l1anufacturers ａｳｳｯ｣ｩ｡ｴｩｯｮｾ Chicago

American Standards Association, New York

Gypsum Lime and Alabastine Canada Ｑｩｭｩｴ･､ｾ Toronto

Toronto By-Law No. 9868, Toronto

Central Mortgage and Housing ｃｯｲｰｯｲ｡ｴｩｯｮｾ Ottawa

National Building Code of Canada

Portland Cement Association of Canada

Department of Scientific and Industrial Research, Great Britain

Netal Lath Manufacturers Association9 Cle'\reland.

Metal Lath Manufacturers Association, Chicago.

Standard Metal Lath Specifications for Better Plastering and Concrete StUCCOo 19360 16po

Metal lath shall be applied with the long dimensions of the sheet across the supports; rib lath with the ribs against

the supports. For exterior stuccos sheets shall be horizontal;

where self-furring lath is used the furring shall be placed against the supports.

]

.

•

,

= 2

-Sheets shall be secured by nails or wire ties

at

intervals not exceeding

7

inches, and a tie, nail or other

attachment shall alvJays be placed vlhere sides of sheets lap at supports and" on side laps half way bet,,-reen supports; provided further that ties of side laps" shall in every case

occur as not to exceed Ｙｾｩｮ｣ｨ intervalso

Expanded metal reinforcement for concrete stucco

shall be lapped at sides and ends by one full diamond0

For exterior concrete stucco drive nails or staples so they afford liS-inch clearance between it and the exposed

surface of the' latho Nails shall be bent upwards and not

dOi,mwards0 Furring or common ｮ｡ｩｬｳｾ staples, ･ｴ｣ｾＬ shall be

driven at least every 16 inches apart horizontally and not

more than

6

inches apart vertically for regular mesh latho

For expanded metal reinforcing (stucco mesh) spacing of nails

shall not exceed 8 inches on centres in both directionso If

self-furring lath is not used, then self-furring stucco nails should be used to provide at leastl/4-inch furring space

between back ｾｩ､･ of lath or stucco reinforcement and the

backing0 Crimped furring or 3/16-inch pencil rods may also

be used for furring, wood furring should not be usedo

Before application of metal lath for stucco work metal flashing shall be applied at water tables, over all door

and window ｯｰ･ｮｩｮｧｳｾ wherever projecting woOd trim occurs, at

ends of sills, and at all horizontal courses and else\vher-e 't"herever "'<Jater might remaJ,n on or get behind stuccoo

Ｌｩｬｬｑ･ＮｲＱＭｾｮ Standards Associat,.iou.

Proposed Standard Specifications fer Portland Cement Stucco and

Portland Cement Plastero May ｬｬｾ

19380

Metal reinforcement shall be applied with the long

dimension at right angles to supports and shall be securely

attacheJ thereto at 8-inch intervals ,-,lith approved type furring

nail or device which holds the reinforcement away from the

supports at least ｬＯｾ inch0 Sheets shall be lapped at least

2 inches at ends and sideso

Hasonrz Unit_5

ＨｾＩ Concrete masonry surfaces should be rough, at least

comparable to a carpet float finishQ

(b) Clay tile should be burned and scored to provide

• t

(c) Clay brick should be well burned and sufficiently coarse in texture to provide mechanical ｢ｯｮ､ｾ

(d) Soft burned or glazed tile or brick do not provide proper mechanical bond and should not be used.

(e) Portland cement mortar or portland cement and lime mortar should be used in joints, raked out or cut flush.

(f) Metal reinforcement should be provided wherever surfaces satisfactory for application of stucco are not

otherwise proyided and wherever stucco is carried over flashings. Gypsum Lime and Alabastine Canada Ltdo, Toronto.

Specification ncw - _{Exterior Stucco on Wood Frame Construction.}

1950

0 3po

Crystalite reinforcement must not be pulled tight into' external angles, as it is essential that the stucco coats be properly reinforced at these points.

(1) Secure a strip of reinforcement or expanded metal vertically over the external angles and extending at least 6

inches on each side leaving it loose at the angle;

. .

(2) Erect crystalite reinforcement horizontally starting at the-base of the· wall with the crimps in contact with the felt and overlap all horizontal and vertical joinings at least 2 inches;

(3) Secure to wood studs at

4

inches on centre vertically 'by nailing through the sheathing with 2t-inch nails;

(4)

Turn the head of the nail over the crimp in the wire; (5) The reinforcement shall be applied over the strips at external angles, thus providing double reinforcement at these points.

Gypsum Lime and Alabastine Canada Ltd., Toronto.

Specification "Bft - Exterior Stucco on Masonry.

1950.

3p. Soft or painted ｭ｡ｳｯｮｲｹｾ weathered brick which has spalled, smooth concrete or tile, or any other masonry which lacks the required strength or key to support stucco must be covered with a metal reinforcing ｦ｡｢ｲｩ｣ｾ securely anchored to the wall. Providing the mortar has sufficient strength, the fabric may be secured by nailing into the joints of unit masonry.

f

,

ｾ

4

-Apply crystalite reinforcement horizontally with

the crimp in contact with the masonry. Overlap 2 inches at

all vertical and ｨｯｲｩｺｯｮｾ｡ｬ joinings. The reinforcement shall

be secured into the mortar joints with large-headed galvanized'

nails using two nails per square foot of wallo The length of the

nail required will ､･ｰ･ｲｾ on the strength of the ｭｯｲｴ｡ｲｾ The

longest nail which can be driven without bending is recommended.

Toronto By-Law Noo

9868,

revised June 24,

1940.

Section

3,

Lathing

(5).

p1510

Metal lath, '''ire lath, and wire fabric shall be attached along the length of the supports, at interva.ls not exceeding 6 inches, by nails or staples with a penetration not less tha.n 1 inch or by soft annealed wire ties not less than

No

o 18 gauge in thickness, or by some other equivalent meanso

In wood-frame construction such lath shall be attached by

nailing through the sheathing, if ｡ｮｹｾ to the studs.

Central Mortgage and Housing Corporation, Ottawao National

Housing Act,

1944

0

Building Standards (Excluding Apartment ｂｵｩｬ､ｩｮｧｳＩｾ Section 42,

Stuccoo p56 ..

(a) Stucco shall be run either direct on concrete

surfaces or on galvanized iron expanded (or other) metal lath

weighing not less than 3 lbo per square yard fastened to wood

furrings at least

31Btr

_{thick at 12}ft _{on centreo Stucco shall}

not be run direct on brick surfaceso

(b) Flat or expanded metal lath shall be applied on not

less than

.3/B"

_{furring strips at l2}9f _{on centres o'verbuilding}

paper on the sheathing.

(c) Furring strips may be omitted if 3/819

ｧ｡ｬｶ｡ｮｩｺ･､ｾ

self-furring rib lath, vleighing not less than 3 lbo per, square

yard is nailed with large headed galvanized nails to provide a

3/8« _{key for the stuccoo}

(d) 16 gauge galvanizedvrire fabric or Noo 20 gauge

galvanized lit x 1U loop '''ire applied to 3/8n x 7/8" furrings

at ＱＲｾ on centre or nailed with flat headed furring nails which

"rill ensure the wire being held 3/8" _{from the sheathing? may}

'be usedo Nails shall be spaced not more than 12" on centreo

(e) Western Red Cedar lath? NOn 2 or better grade will

be permitted for stucco work on Vancouver Island and the

lower mainland coastal region of British Columbia. Other

Central Mortgage and Housing Corpo ation, Ottawa. National

Housing Act,

1954.

Building Standards (Excluding Apartment Buildings). Section

40,

Stucco" p68-69.

(a) Stucco may be applied directly to any clean, sound,

rough masonry surface, excepting ｳｯｦｴｾ｢ｵｲｮ･､ brick and sandlime

bricks; also to metal reinforcement and lath described in (b) follov!ing.

(b) Stucco Reinforcement and Lath

I. All metal reinforcement for stucco and fastening,

shall be galvanized, or as listed in "Acceptable

Building Naterials, Systems and Equipmeilttf_•

Expanded sheet metal, or welded or woven ｦ｡｢ｲｩｾ

is acceptable in the following weights or gauges: (i) Expanded, galvanized sheet metal- reinforcement shall weigh not less than 2.5 Ibo per square yard;

(ii) Welded or woven wire fabric shall weigh not

less than le2 ｉ｢ｾ per square yard before galvanizing.

Wire gauge shall not be smaller than Noo 18 for

meshes up to 1" and not smaller than Noo

15

gauge

for meshes ",rider than 1". No mesh shall be greater

than 2"0

(iii) Metal reinforcement may be either flat or self-furring.

20 Western Red Cedar lath, Noo 2 or better grade, will

be permitted for stucco work on Vancouver Island and the lower mainland coastal region of British Columbia. Other species of wood will not be acceptable for

stucco lath.

(c) Application of Stucco Reinforcement and Lath

I. Stucco reinforcement shall provide at least

3/8"

stucco key. This key shall be obtained by the use

of furring strips, self-furring reinforcement, or furring nails.

2. Reinforcement shall be nailed "rith either large

headed (7/16" heads) roofing nail, ｳ･ｬｦｾｦｵｲｲｩｮｧ

nails, or staples having shanks of 10 gauge vJ1reo

No dependence shall be placed on gypsum sheathing or fibreboard sheathing for the nailing support of

furring or metal lath. Nails or other fastenings

,

J

- 6 ｾ

3.

When reinforcement is applied by driving nails

through the sheathing into studs, nails shall be spaced not more than 6" apart vertically and 16"

horizontallyo When sheathing is gypsum or

fibre-｢ｯ｡ｲ､ｾ nails shall penetrate into the studs at

least 14"e

4. vIhen reinforcement is applied by fastening in

patterns different from (c) 2 and

3

preceding, or

over horizontal furring, at least 16 nails shall be used for fastening each square yard of reinforc-ing material.

5. Wood lath shall be applied over :/8" thick 'lATood

furring strips spabed not more than 16" On centre. Nails shall be galvanized and shall be not less

than 16 gauge with

It"

long shankso

Canada, National Building Code 19410

Stucco on Wood Frame Construction. Part

3,

Section 8, Article

5.

30

ｰＱＸＵｾＱＸＶ 0

(a) Back Plastering - except as provided herein, back

plastering hall be required where sheathing is ｯｭｩｴｴ･､ｾ It

shall be of sufficient thickness to extend back between the

studs a dis vance of not less than 1/4 incho Back plastering

may be omitted vmere stucco fulfilling the following conditions is used:

(i) the stucco is backed with a water-proof paper;

(ii) a test panel shows a racking strength not less

than that of a standard panel having horizontal

wood sheathing of 5/8-inch ｴｨｩ｣ｫｮ･ｳｳｾ when tested

in the manner described in Appendix Co

(b) ｾ､ｩｮｧ ｐｾｾｾ - in all ｣｡ｳ･ｳｾ except in back

plastered construction. ｡ｳｰｨ｡ｬｴｾｳ｡ｴｵｲ｡ｴ･､ felt weighing not

less than 14 Ibo per 100 square feet, or any substantial

water-resistant building paper which passes a 60 pound Mullen test, shall be applied directly over the studs or sheathingo

Felt or paper shall be lapped

4

inches at all joints and

around all openingso

(c) Reinforcement - stucco, when backed by sheathing,

shall be reinforced with metal lath weighing not less than

108 lb. per square yard and having openings, the least

dimen-sion of which is not less than

3/4

inch and the maximum area

ｾＭＭＭｾＭＭ

-ｾ

7

-reihforcement weighing not less than 101 lb. per square yard and having openings not more than 2 inches square

(Noo 16 gauge ,,,ire) may be used. \Vhere sheathing is Om' tted,

the weight of such metal lath shall be not less than 3.0 lb. per square yard.

Metal lath shall be galvanized or otherwise

effectively protected against corrosion, and may consist of

expanded metal lath, wire lath or

wire

_{fabric. It shall be}

furred away from sheathing or building paper' at least 3/8 inch at all points by the Use of special furring nails or devices or by suitable metal strips unless self-furring metal lath is used.

Canada, National Building Code 1921.

The Application of Exterior Stucco as Claddingo Part

4:

Design, Section

4

08: Cladding? Appendix

4

08.J.

General

Stucco shall not be applied directly to soft burned

clay tile, brick ｭ｡ｳｯｮｲｹｾ or backings of lower strength than

stucco.

4.8oJo2.302 Frame Construction

(a) Sheathing Paper (Breather Type)

Sheathing paper shall be applied to all forms of sheathing and shall be breather type asphaltic sheathing paper

complying with the Specification listed in Part

5:

ltIaterials.

Tar saturated felt or paper shall not be usedo

(b) Stucco Reinforcement

Stucco reinforcement shall consist ofg

(1) galvanized wire fabric of not less than l6=gauge

wire having a mesh opening not greater than

4 square inches. The fabric may incorporate a

furring device having a depth of at least

5/16

inch or may be flat, in which case it shall be attached with furring nails.

(i1) Expanded metal or wire lath shall weigh not less

than 3.0 lb. per square yard and shall be applied to 1- by 2-inch wood furring strips spaced not

8

-metal or "fire lath shall be secured to the

furring strips with galvanized nails 'or staples spaced at 6 inches on centre, and have sufficient length to provide not less than I-inch penetration. Reinforcing fabric shall be erected horizontally, with the horizontal joints lapped at least 2 inches and end

joints-at least 4 incheso End joints shall not occur within 16 inches

of any corner and only over studs. External corners shall first

be enclosed with a vertical strip of fabric' extending

6

ihches'

on both sides of the corner to provide a double layer of fabric at corners after the continuous reinforcement has been applied. 0fuere stucco reinforcing fabric is applied to gypsum, fibreboard,or plywood sheathing, it shall be nailed through the sheathing into the studs using large-head galvanized nails of sufficient length to provide at least I-inch penetration

into the studso Nails shall be spaced not more than 4 inches on

centre verticallyo

Horizontal joints of metal lath shall be lapped I-inch

and tied at a point midway between the furring strips" End

joints shall be lapped 1 inch and lapping shall occur only on furring"

Portland Cement Association"

Plasterer9_{s ｍ｡ｮｵ｡ｬｾ 32po 19520}

I" Frame Construction

Attach reinforcement securely; nailing or stapling it' flat against the face of studs or sheathing is poor practice" Have it furred out at least 1/4 inch so that the stucco can'

be forced behind the ｭ･ｴ｡ｬｾ Use furring nails or other furring

devices that will not reduce the thickness of the stucco"

Nails should have a penetration into supports of not less than

1 inch" Solid furring strips which cut into the stucco slab

are objectionable as they make lines of weakness and may cause cracking"

2" Hasonry

(a) Hard or medium clay ｢ｲｩ｣ｫｾ unpainted and with joints

raked or struck flush, should receive three coats; scratch, brown and finish"

;

.

9

-(b) Soft" clay brick or brick without rough faces or

painted brick require the following: 151b. building paper,

metal reinforcement furred out 3/8 _{inch with furring nails}

8 inches on centre. Minimum weight of lath ＱｾＸ Ib o per square

yard.

Minimum opening 3/4-inch square, maximum opening 2-inches square.

(c) Reinforcement not required for concrete and clay

furring tile.

(d)" Solid furring strips which cut into the stucco slabs

should not be used.

(e) Old masonry walls softened by weathering,' surfaces

that cannot be cleaned thoroughly such as painted brickvlork, and all chimneys must be covered with metal reinforcement before applying stucco.

Great Britain, Department of Scientific and Industrial Research.

Plastering on Metal Lathingo Digest Noo 14,

1950,

5po

Reports received at the Station indicate that the most common defects found in plaster on metal lathing are extensive cracking? particularly along the' line of fixin.g of the lathing to its'supports, or of unevenness of the finished

plaster ｳｵｲｦ｡｣･ｾ or of ｾｨ･ｬｬｩｮｧ of the finished coat from the

undercoat or of ｣ｯｾ｢ｩｮ｡ｴｩｯｮｳ of ｴｨ･ｳ･ｾ

The lathing must be fixed and tensioned as lightly as possible.

Plain expanded metal lathing should have' a weight of

at least

3

ｉ｢ｾ per square yard when it is used over normal

supports at 14 inches on centreo For wider centres heavier

lathing should be used in accordance with the makervs recommendations.

ｾｦｵ･ｮ metal lathing is applied to timber supports

it must be secured by galvanized nails or staples driven skew-wise across the grain of the timber at 4-inch intervals.

Metal Lath Manufacturers Association, Cleveland.

Reinforced Portland Cement Stucco. Technical Bulletin No.1,

March 1952₉ 4p.

Metal lath or stucco mesh shall be attached at not

greater than Ｖｾｩｮ｣ｨ intervals vertically and 16-inch

intervals horizontally with galvanized nails haVing a

,

= 10

-into horizontal wood supports of at least

It

inchesc It"

shall be spaced from the backing not less than 1/4 inch with

furring nails or devices, or self-furring metal lath may be used.