Mortar Mixes and Height and Thickness Requirements for Masonry Walls Above Grade (A Comparison of Building Code Requirements)

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Technical Note (National Research Council of Canada. Division of Building Research), 1959-08-01

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Mortar Mixes and Height and Thickness Requirements for Masonry Walls Above Grade (A Comparison of Building Code Requirements)

Hansen, A. T.

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NATIONAL RESEARCH COUNCIL OF CANADA

DIVISION OF BUILDING

'IF

ECIHlN JICAIL

RESEARCH Ｈｾ

N

0']['

JEY

No.

287

NOT FOR ,UBLICATION

I

PREPARED BY A. T. Hansen CHECKED BY WHB

FOR INTERNAL USE

APPROVED BY NEH

PREPARED FOR Subcommittee on Construction, Cladding DATE August

1959

and Materials, of the Special Committee on

Housing, Associate Committee on the National Building Code.

SUBJECT

MORTAR MIXES AND HEIGHT AND THICKNESS REQUIREMENTS FOR MASONRY WALLS ABOVE GRADE (A Comparison of Building Code Requirements) This note was prepared for use by those who are engaged in preparing the Housing Code Section of the National Building Code, in order that they may conveniently compare the requirements of other code and standards authorities.

The requirements are tabulated for convenience so

that rapid comparisons may be made. ｾｮ such

a

form, however,

complete requirements are not always included, but the tables do include those which are considered to be the most essential.

It will be noted in the listings that most of the codes and standards prepared after the 1953 revision of American Standards Association "BUilding Code Requirements for Masonry" have been influenced by this document and in

many instances have identical requirements. .

It will also be noted that the Canadian requirements, at least for thickpess and height, are more restrictive than

most for some types of walls. For instance, all of the other

codes and standards except one permit the use of 6-inch

masonry walls whether of solid or hollow units for one-story houses, whereas the existing National Building Code requires a minimum thickess of 10 inches if hollow units are used and a inches if solid units are used (unless clay bricks are used, in which oase 6-inch one-story walls are permitted).

, Although the DBR Housing Standards permit the use of a-inch walls of hollow units, or 6-inch clay brick walls,

there is no separate requirement for non-bearing partitions which must be assumed to be the same as for bearing partitions.

•

2

-Mortars

The mortar requirements in the National BUilding Code are such that any of the suggested mortar types may be used in

any location without regard to exposure conditions or type ｯｾ

wall, except that the various mortars must have certain minimum strengths.

The Housing Standards do restrict the use of certain

mortars, but the wording of the Standards is such as to suggest

that the strongest type of mortar (cement mortar) has more restric-tions on its use than the weaker lime-cement mortar.

It would appear, therefo+e, that there is considerable

room ｾｯｲ improvement in the present Canadian requirements both

for minimum wall thickness and allowable types

of

mortar.

Since the ASA standard has been used as a guide for the requirements in most of the later codes, it would appear that this is the logical document to use as a guide in preparing the new Housing Code.

The folloWing is a list ｯｾ the various codes and

standards used in compiling Tables I and II:

A National Building Code of Canada (1953).

B Division of Building Research Housing Standards (1959).

C American Standard Building Code Requirements for

Masonry ASA-A41.1 - 1953.

D Federal Housing Administration Minimum Property

Standards for Oneand Two Living Units (1958).

E New York State Building Code (1954).

F ｕｮｩｾｯｲｭ Building Code (1958). International

ｃｯｾ･ｲ･ｮ｣･ of BUilding Officials.

G Southern Standard BUilding Code (1957-58). Southern

BUilding Code Congress.

H Basic BUilding Code (1955). Building ｏｦｾｩ｣ｩ｡ｬｳ

ｃｯｾ･ｲ･ｮ｣･ of America.

I Midwest Building Code, Vol. II (1955). Midwest

Conference of Building Officials.

J Building Code Requirements ｾｯｲ New Dwelling

Construction. Building Materials and Structures

Report BMS 107, u.S. Dept. of Commerce, National

e

_e

TABLE I

Max1.mum Height and ltlinimum Thiolmess for Mas0J;lr1 Walls and Partitions

e

,

ｾ

Exterior Bearing Walls Cavity Walls Interior Bearing Walls In"&enor 1'Ion-oear1ng_Partitions Veneer

Reference Solid Units Hollow Units .-Solid Unit8 Hollow Units Solid Units Hollow Units

Thick- Thick- Thick- Th1,ek- ＺｉＺｮｾｃｬｻＭ ＧｬＧｮｾ｣ｊｻＭ TlUcJ{- ＺｌＺｮｾｃｬｻＭ

-Height ness Height ness Height ness Height ness Height ness Height ness Height ness Height ness

(tt) (in.) (tt) (in. ) (:ft) (in. ) (tt) (in. ) (ft) (in. ) (ft) (in. ) (ft) (in. ) (ft) (in. )

9(f) 6(a) 25 10 35 (b) 9, 6(a) 25 10 1/36Ht. 1/36Ht. 35 3t(a)

A 25 8 35 12 25 8 35 12 35 6 (c) 35 12 35 10 35 4 (d) -B 9(1')_{(g) 8}6(a) (g) 8 25 10 (g) 8 (g) 8 (g) 8 (g) 8 35 3-f(a) 35 (e) C ₃₅9(1') ₈6 ₃₅9(1') ₈6 25_{35 over 10}10 ₃₅9 ₈6 ₃₅9 ₈6 1/36Ht. 1/36Ht. (g) (g) D ₃₅9(f) 6 9(1') 6 25 10 1 floox 6 1 flOOI 6 (g) 3 (g) 3 (g) 4 8 35 8 (g) 8 (g) 8 E ₃₅9(1') ₈6 ₃₅9(1') 6₈ 25₃₅ 10_{14 35}9 ₈6 ₃₅9 ₈6 _l5(m)l2(m) ₄3 _l5(m)l2(m) ₄3 35 2 F ₃₅9(f) ₈6 ₃₅9(1') 6₈ 35(k) 8 ₃₅9 ₈6 ₃₅9 ₈6 2 2 20 (b) one- one ..

G story₃₅ 6 sto17 6(h) 25 10 1/24Ht 1/20Ht. 1/45Ht. 1/45Ht. 20(i) l-5/8( j)

8 35 8 35 over 10

H Not specified, althOUgh ASA 41.1-1753 (Ref. C) is listed in this code under aooepted engineering praotice.

I 20(1) 8 20(1) 8 10 10 20 8 20 8 2 2 20 (g)

J ₃₅9(1') ₈6 ₃₅9(1') 6₈ 25_{35' over 10}10 ₃₅9 6_{8' 35}9 ₈6 ₁₂9 2(n)_{3 12}9 ₃2(n) (g) 3t Notes to Table I:

(a) Rerers to olay briok units

(b) Same net area as for solid ｾｬｬｳ of same material (c) Stone veneer on wood frame

(d) Stone veneer on masonry baok up

(e) 6 in. or not less than t the height of each unit (f) May be 15 1't to peak (g) No l1mit given

0:

in. min.) (h) (i) ( j) (k) (1) (m) (n)

Min. compo strength 01' 2500 psi (gross area) May be 35ft on masonry baok up

Must be 3 i t if hollow units used Some doubt regarding interpretation May be 30ft to peak

Walls not more than 20 ft long Walls not more than 6 1't long

I

4

-Mortar Mixes and Use Mortar Mixes (By Volume)

R("renoe

Line Portland J1atural Maeonq Gypsum Aggregate perpart or

Oement Oement Oement CementtttouB

material PeJ:1llis.ible U"" A 1 -! to 2 1 1110 to!- 1 1 1 1 } } } 1I0t apeoUied Dot "p"oiried 1I0t spe011'ied Bot soeci1'1ed !lot "pecUied

lion-bearing interior partiticn. or bearing Partitiona or

｡ｯｾｩ､ units B

.,

D E 1 1110 to !-,. to U. 1.J- to ?! 27to 4 1 1 1 1

1

1 1 1 1 1 t 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 (a) } } } } } (el ｾｩ ｾｾ ｾ 2 to) 2 to} 2l- to } U to}

2*

to } } (a) ｾ

i:

ｾ 2 to} 2 to} 2 to} 2 t o ' 2+to } Ｒｾ to } 2 to} 2 to} 2-1 to } 2,1-to ,

May ba used in ail 10cationa

Maybe used in all locations except ..alls exposed to ..eather

Non-bearlnit interior partitions only .May be use,) in all locations

Foundation ..aIls and piers of ell locations except tess than

12 in. thick in high ...ind load areas. and 11nin," of

ex.1s1;in/l: mascnry

Walls above grade or solid masonry or non-bearing partitions

Walls of solid masonry not less than 1 in. thick nor more than }5 rt high suppOFfed latterally at intervals not exceeding 12 times the thickneas

Ilon-henring partitions May be used in all locations

All locations except foundation ...110 and piers of hollow

units orODvt'h ""U.

Walls (except roundation ,,"lla) of solid units Rnd non-bear1= nartitions only

May be used in all locations

May be used in all locationa except roundation Mallo 8 in.

end lees made Ofhollo.. unite

Solid masonry wells either less than 12 in. thick or laterally supported at intervals greater than 12 times the thiokness (not both)

G H I 2!to 4 1 - - - 2:1- to } tto4 1 - - • 2*to 3 -i to 1 1 - • . 2:1- to } - • - 1 - 2f to 3 1:1-to 2 1 - - - 2:1-to 3

*

1 _ _ _ 'to} 1 - 1 - 2 to} l-toi ｾ - - - 2 t o } - ... - 1 - 2 to 3 , to 1 1 - - - 2* to } - • - 1 - 2* to } 1 to 2 1. - - - 2 to} - - - 1 - 2 to 3 ｾ to :I' ｾ to 11 : Ａｾｬ

:

ＡｾｬＺ ｾ to

'*

ｾ : : (h) : (b i (s) ｾ (e)

No mixes providad - spacifies minimum strength only

Solid masonry ..aIls not less than 12 in. thick laterally

Ｘｕｾｲｴ･､ at not less than 12 tiMes the wall.thicknsB8

Maybe used in all locations

May be uaed in all locationa except foundation wells Not speoUied

Non-bearing interior partitions only

May be used in all locations

All walls exoept foundation walls and piera of hollo.. units or cavity wslls subjected to high wind DrBSBure Walls of solid masonry or

ｮｯｮＭ｢･｡ｲｬｮｾ partitions

Not specified, although ASA41.l-19S3 (authority C) is listed

in Appendix Bto the code under sccepted engineering

practice J oto t 1to 1.1: 1 1 1 1 ], 1 } (01 ., (0) } }

.,

(0) }

All wells exoept 10 in. cavity ....110 and foundetion wells of hollow units and linings of existiny. buildings

1I0t speo1!led

Solid masonry walls above grade at least 12 in. thick and not more than 35ft high, laterally supported ot 12 times the wall thickness

Notes to Table II:

I

(a) Proportions by ...eight.

(b) Code gives ｰｲｯｰｯｲｾｩｯｮｳ in terms of "Spproved cement". It is not established whether or not natural or

masonry ｯ･ｭｾｮｴ is intendad8S ..ell as Portland cement.