Soil Problems Connected with Foundations for Basementless Houses

(1)

Publisher’s version / Version de l'éditeur:

Technical Note (National Research Council of Canada. Division of Building Research), 1953-03-06

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/10.4224/20338445

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

Soil Problems Connected with Foundations for Basementless Houses Peckover, F. L.

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=5659ac0a-2a6c-4895-8254-ce712c5fde57 https://publications-cnrc.canada.ca/fra/voir/objet/?id=5659ac0a-2a6c-4895-8254-ce712c5fde57

(2)

PREPARED FOR ｾ

6th

M

rch

1953.

FOR INTERNAL USE

APPROVED BY

NOTlE

CHECKED BY

DIVISION OF BUILDING RESEARCH

'Jr

_E

_C

_{1HIN II CAlL}

SUBJECT 011 Probl Oonn cted with Found tiona tor

a ntl _a Hous e .' Reprinted trom the

Proc. inga

ot

_th _{Sixth Soil M chanioa}

Cont renee held in Winnipeg on D oember

15th

nd 16th,

1953,

un er the autpice. ot _the

aocl t Co itte on So11 and Snow echanloa.

In thinking of the eua t ry appl1c tiona of so11 chanl0,

w thlnk

ot

_larg _{buildings and brl} _j _tunnel _{, ro da}

and railv ya. S Idom do w co Id r th 0 t cartmon pplic tlon

--In the d aign and construction of ordinary houae foundationa. Thi.

oversignt 1 ually because uCh pplic tio or oil echanic ar

not made dir otly by the designer or builder but rather' indirectly

through th applic tion ot _{building cod} _{Which i} _th _{result or}

accumulated experience.

PREPARED BY F. L. Pe kov r NOT FOR PUBLICATION

Building cod a sp olty the d pth of house foundationa and the

various prop rtlona of baa nt campon nta, in order to protect the

af ty and h 1th of th public. Th re 1s little scope left 1n

d 19n1ng foundatIons, an operation which bee es a matter

ot

_following

s t of rul a.

,

This trad! tional pic ture baa been interrupted in Canada in .

recent year8 by new concept in housln -- the baa entle.. houa •

This type of dwellin ha Ine popul rIt,. in the earch for a lower

coat hoWl in apite ｯｾ the sea ity ot present knowledge about Its

relatlve d antag . , diaadvant ea, and proble •

From an eoon io point of view, 1 it d s1rable to build a

baae entles. hoWl und r Canad1 n c1 tic conditlona? This i a

most complieat d questlon and w in the Division ot _{Building Rea arob}

r at present att pting to tind an anawer. So tar, it i. only known

for cert in that the answer will not be a imple yea" or no" but

uat be ti d in with variations in climate and apaoe r q,ulrem nta

ot

the Ind.ividual.

The engineer1ng probl a raiaed In baa n t l . house

oon-atruction ar many nd important -- and in general they are not yet

dealt within building cod • Th re ar two important exception

(3)

....

-...

l' llow d by the W1nn1p g bUilding cod and by the new rv1.ed

t10na! Building Cod. 1ch hould b

art

_the

_pres

_ar17

_{n xt}

_year.

In th dea 19n O'E bas entl • hous.s, withou.t any que.tion,

foundation

d

sign

lone ot

th t o o t ditrl

ult

eng1n••r1ng

proble

•

The other

1

the qu .tion

ot:

_ｰｾＮｐ _he _t1ng _ayat

_wh1

_h

1t

ia not

our plae

0

d1

u

her.

Design of a foundation tor

ueb

house do _ not erel,. oonsist

ot

₈₁ _inating _he _baa _ent _and _au

-atltuttng a con rete

.lab

On th

round.P'undamentally.

the simple t

toundation woul be euchal b. rv1ng

to distrIbute the 10

cl

from

xterlo1" and

1nter1or·

wall$. and

ct

s

ｴｬｯｯｾＮ 1'o.e

it eueha

lab 1s

au.f't1c1

nt, the

f

roe

a fi1

up n

it

tx-om

_oth

_{s14•• 'houl}

be cOM1d.e1'ed.

the a1 b a1' known. BUt the

1 b d

pen

ntlrely

v n or unev n.

It

n

e a

or gray

1, then an

1c1ent

to

d1 trlbut

th

load.

Unven 'pport c n only

underly s 1 to flo

or c

n

are too mall to in u e flo 0 0

developed by ·olume 0 e of h

b ue t ch ｾＱｧＮ in the vol e 0

pI' ot1c 117 inc pI'. i· lee 0 ih ar!ous m an by libich

8011 volum.

may chang., comprea ion du to uper 0 e" 1· ad. or th cons llda ion

of 100$ t r1 1 111 not pply to 011 und r hou e slAb It it la in

properly co pacted stat·, s should 1 b . sp c1t1ed. iml1ar11.

a basementl••, ｨｯｾ 'Whioh is p Qpeply de 19ned to allow cert in

ount

ot

_h _{t 10.} _{l'tound the} _p _{r1m tel"} _hou.ld _not _b _{aubjet to} _troat

aotion Ln the underlying a011. T 0 potential sourc a

ot

oil

volume

chang are therefore not pp11c 1 und r Qrdinary coneli

tlonJ.

Swelling

nd ahrlnkag ot 011 r &ins the gre t pot nt1al us ot

damag

which cannot be controll d, nd thl ph nom non 1 worth disouasing in

om. d tall.

S••llb and _hrlnkag 1s atr10ted to so11 hieh cont In

an

apprec1abl

p rcentag

ot

_{certain 01} _y _Ineral _Which

_have

_the

property of orbin or r le in ter 1n th Ir crystal tructur.

nd hene

t

_i _vol _on _and _drying. _{It a} _foundat10n

lab is built On such 8011, vol change 1 lmoat c rtain to oecur

1nce the outur aondltiona und r wh1ch the oil striving t l ' ach

equilibrium ar cha ....

S 11 01 tur 1_ 1'1 11 1n.fluenced by ita en .1roDl1ent. on

any

plec:

ot

_{ground, ra1n vhI} _tall _ontribut ₈ _to _r1a _{1n th}

round t r table nd. an in reas 1n th 01 ture h 1d in the soil

abov th t 1e..,.1.

Th

r

indor rw18 ort

on

th ground surtace. That

(4)

evaporatIon and tramJplration at e groundaurtaee ',n4 roota in the

bOdy

or

the 011.' Th1 suction Y 1 . .pendlng on . ob ｣ｾＱｭＮ｡Ｑ［ｩＮ

tactora a

t per

ture, sun-hin

d

ｲｬ｡ｾＱｶ･ humid! •

Th

oiature

at anJ po1n't in th g1"ound 1. co

tantly _

tr1v1ng to,,", each a b lance

b tv en th supply of. tep trom below and the drlclenCl

or

olature

Er bov' -"" or vIc. VI-a en It ｲ｡ｬｾＮ If, nVironD1ental

con-4Itlol1$ r main ateady a b 1 nc will b ro ehed. Butot coura the,. n vel" do and ｭｯＱｓｴｵｾ in th aol1 1 a1W 1a . ,"owly moving.

When a oOYering such a house tOWldatton ala\) 18 plaoed on he ground urtace,. the sUM' 08 uctlc>n du

to ,vaporat1on

and trna-plratlon

1. uddenly

ｾＱｭｩｮ t.d over t

t

｡ｲ･｡ｾｾ･［ｵｮ､ＮｲｬｹＱｮｧ so11 the.r'fore

t1nels IteU tre

to

absorb

.ddltlonal

mo1atur ,.

1ta

mol ture cant nt increases lind h nee, in

the

c e

ot

_{a clay SUbject to}

vol

ｾ･ ohang # the

volume

inol' ,

e.

Under

the dg

ot

a 81 b the qu111br1um of 011

_moutu

_{111 atl11 b} _:treoted by the

mo!.tur.

exc. s or d tlclency in the adJao nt uncovered 011. Th retor , aa

might be

ｾｰ･｣ｴ･Ｎ

the

ctual

011

oi ture distribution

aeross a

seotion und.!' a lab, wlU in dry . e th :it :tange

tr-om

..

maxImum under the GentH.

t

the m1n1mum ｰｲ･ｶ｡ｬＱＱｮｧｾ out&ide th .4S. of th slab. This dl.trlbution

ot

_{moisture reflects the} _{ｉｮ｣ｾ･｡Ｎｬｮｧ} _{influence ot}

cl1tnatlc

nnronment

trom

_the _entr

ot

_the _slab _to _thtt _{outsid.••}

Th1 cone.pt 1. known th 018 ture quil1brlum.

the01"1.

moat ably propounded by Oron.,. of th Ro d R .arch

Labol"atory

in Brita1n.

There

1s a m, jor

plio. tin

actor. It 1s wll ｫｮｯｾ that oisture in mater! 1 in w h l o h t u r e gJ-adl nt xists travel_

from hot to co ltl zoeglona. '!'hi 18 1 0 tru Inollaand quantities

ot

_.

_ter _y _e

_t1'

_nit

_rred

_1n _{th1 'w1} _{ccord1ng to the la_}

ot

th rmodynam1ca. An ｾｰｬＬ of this ols tur Dl1 rs.t lon haa ben d••crlbe 1n 11ter tux-. D· e 0 ourred. to the found tlon

or ..

bkerJ Whr

Qvenawere pre

ｾｭｴＮ

l,t

.

l a l••

ov·ared tha.t .. marked

d.ecrease 1n '011

molature

bad t n plao in the ':rm. J' ona und r

the C)V na, with Qorr .ponding d ere • in so11 volum II Most or the so11 01 ture conoern d did not apor t but 1" therlgrated to a cooler spot.

111'14 Ｎｾ Canadian 01 'tic ｯｯＱＧＱ､ＱｴｬｾＮ th foundation ,lab

ot

_a

hona 1. at pprox1mately th

a

temper,

ture,

as the top 1a1_N t

th

ground1n

er..

and the th rm. .. •

ott

erteat would thereto"

not be

tmportant. In

w1nter.

ho .

vel".

when the slab

14 lPlrm,

moisture

t$n4a to 1111grat . down ..·rU

and

out N. In ina

tane..

a hlp••

ground

water table during the

W1nter,

onths

may

tend to counteract ｴｨｾ

tl

ot.

₀₁ _{ture.lt will be not d} 'th,t th chang 11'1 soil ll101ature d volume UI1der the entre ot the lab du to this etlon 1

in

the opposite dlr

etlon'

to

that

1Ihlch

would be ｢ｲｯｵｧｨｾ about by the

mol.tun

eq I11brlum theory. Th' whole question 18 ther tore complicated and

(5)

th QJ!7

governa.

Scattered 00 ｾ rv tlons of

centr

h

'.ving

under house

. 1 ,ba in Tex ,_ d South ａｴｾｬ｣Ｎ

w

11 Q in Oanad. • • to indio

t.

PJt d inance of th o1Stur qu111brl theory.

The ett.t of founding ,coner t slab on Illng and ah:rlnld.ns

clay is, th r £Ol'e, to . ubj t it to bending

stres..

In 80m dgree, due

to varying . upport b t en

1. t

entre d

dg...

How

ver.

th. . tre a

conditions in the lab "111 b41tl' r

nttor- each

Ind1 14 '1 It. inc.

thet ･ｴｯｾＭ lnv,olVe<l In

vol

•

chang 1n'

011.

d pend 0

1@ge17

on

eond;tt10 . or elm

t

ｾ､ av iIableol t\Ule. In

addItion"

th 8011

itl.t' an the pr nee of tr . 0 hl'Ub lMl.y cr ate specl 1

local

･ｯｮ､ｬｴｬｾ

_ •

'

The P1"Obl . of providing

t1"

ngth 1n

1;h

tore..

app11 d by 0 nt of th und r171ns 8011

prOviding r lrifof'c t and p rhap

Q1:" a gl'i,nul X' tl],l under th 91 b. $'h Wiard;> g Building C • ap citl••

relnfo - ,in . te.

1 t

_lit _{houll. foundation ,- lab} _on _tb _baau _ｯｾ _va:r1oua

uaumpt1oM# on

ot

lch 1 th t th lab

may

at ,SOlae time b

unsupported

tordiatanoe of' ,

t

_1n _ｴｾ _{all edges, due to}

;b.:rlnkg of the unci r171rJ.g 8011. Thl a to prov1d a.tlatattoJl117

for the. xtrent' OOM1ｾｬｯｮ｡ lch '1 b expected on the b 180t present

knowldg .•

4. !he Wlnn1p g Building

00d8

raqu1re

dna

granular till

und.r

house found tlon lab. The 1'1' tional Building Code leave..

tu

de :lgn

ot

_{r Wei- ing} _t8.1

_to

_th _{1 cal authorities,} _but _ka _for

_{. t leut}

6 inch.

of granula.r rill.

Th re 111 ye't no ra'tlonal baai tor actual de, 19n tlguP ••

How yep, a n t t mpt i . bein de in th . Division of l3u11ding R search,

.tional ea' reh

a

Qunol1" to

aiacoy

r th

xt11,"

for

Whloh 4. 19na

ｾ be -d.

. Til Dlv110n _ thr. £1 Id 1nataJ.la.tlo113, two 1n Qtt

and on in Wlnnlp ,on th. pus of the Um.ver ;1tY' o t n 1toba. EaCh

OOllat.

a of

a oono,rete a1 b

foundatlon

20 te.tquare..

prov14

With

a

pretabr10,t4 aupe:retru.¢ us- and h at to ･ｯｾｴ｡ｮｴ t peratur b7 a

radiant h t l n system in th 81 b. 1.1 three install tiona are 1n

loe tiona . her the und r1yln 8011 _1· _l1bj_ect _{to conaid r} _b1. _vol _•

ch __..

o.t

the two Qt. $lab , one 18 pla··4 ､ｬｾ･ｯｴｬｹ on the gl'ound

urf'. and th other 1 upp rt bY'

is

lnch of ｧｾＬ v

1

tl11. The

Wlnnlpe.g install tlon 1 placed dir ctlY' on th ground.

,

(6)

In Ottawa

was

btrllt in the tall

ot

_1951. _{Bo r} _ul_t

ot

_{cons quence} _re

yet a\' ilble sine the weather during 1 t summer

wa

muoh wetter

than usual and the alabs wer', ther

tor.

not .

ubjeot

to th extre.

conditions

ot

₀₁₁

_volume _hangehicb

_w

_r _antlo1pat4.

_Th

_Winnipeg

.lab

was

ll1#"talled thl.

t

11.

It Ill!"'" be

ot

_{1n.ter at} _in _{clOSing to} _ummarlze _s. _'tepa

wh1Ch hou14 b. rEtqured 1n th constra tion

ot

_{b . ,}_11l _ntle.. _h _U8

toundat1ou. .Mot of the .' _ r bas on good cQnat:rro.otlon praet10.1

1.

Theal te ,hould not be 1 v n4 UJl$u!ta.ble ｴｯｾ 0r<11na17

ｃｑｾｴｲｵｴｬｯｮＮ Ithough baentle houaea otter a

solut1on

to so e ･ｯｮ｡ｴｲｵｾｴｬｯｮ problema on sUC'h s1 tea, there

"11.1 al 0 be dift'icult.)" in conatruct1ng them to pertom

aatl.t.etonl,...

2.

The it, hould b ' r 1 ttvel,. level and organic soil

and sod should pret .1,. b remov d.

3.

Proper 4r lnag

ot

_the _it _'hoUld _be _p:rovld _1t

li ter 1s

lIkely

to cumul t aroun or Within the till.

4. on

a go d, lIell-dr in d It.

it

may not be nec. .sa17

to provld more than 6 inch 8

ot

till if the ｲ･ｬ｡ｴＱｾＮ

height

ot

_the _{house and} _urrounding _ground _{is sUitable.}

It is. howev r, de81r hIe to h v the 81 b above adj ent

ground to guard ag 1nat tempor ry acoumulation

ot

_{_ter}

such as from e1tIns s now, and to g1 va splash 01 arane••

S.

_{terproot membrane} _{hould be la1d under} _ｾｨＮ _eoneret.

alabo

r the en lr

found tien area 0 as to

preven.

mIgr t10n

ot

_{mo!s tur.} up rd

into

tlleconcret••

6.. :kc p't in unusual conditions a conol" te foundation .lab

thick r than b Inche hould not be ne(u•••ary and 1n 111&111

lZUJtano..

rdtto.d th1Qkne

.s should b

atlstactol7.

7. Slaba

a,.

be 81th

r

ot

_pl _in _ection

_Or

_{ldthaperlm•••}

-r

be-.m. ｾ･ a ,ount

or

Mlnfo ing to be proVided. In the

conaret. 1. variabl dep nding on .ite condltloM D:1 the

thl

b....

ot

_{t111 PPOv!} _{' .} _Th _amount

ot

_••

_{1ntor 1ng}

sp c1tled in the- Winnipeg

BuildIng

Ood 1.

probably

ad.quat

tor ba4 81te conditlona,.

8. tom at

_hating _,.st _{should b} _{ua d which w111} _upply

heat to th edge

ot

_the _{lab and thUS} _void _cold _floo _•

'!he ｾ dgea hould be prop rly 1naulated to control the amount

ot

_{heat lost to the} _{urroundlng aoi1.}

.

(7)

"-6.

9.

ｉｮｴＮｾｬｯｰ

water and a wage fixture

shOuld b

kept 0105

to

on sid

ot

_th _hous _nd _{ｰｲ･ｾ･ｲ}

_bly

_near

_tn.

_{c ntr}

ot

_,on'

ld& SO th t ｵｮ､･ｲｾｯｵｮ､ repairs will

freo

t th upp rt of the

slab as little po aibl •

ome

or

th .he .y to other technioal

prabl ,loh ve not een disc • 'rhe r qulrem n

tor

_IItructural

s'r ngthust₄

ot

course,. be eo-ord1n t d with other requir . ent' tor

proper heating and building rl'ang . nt to produC n lntesrat

d .lgn, Tbi t in

turn.

MUS 1 .1 It 'to conom.lc 1 . onstructlon.

CUl'I' nt PI' ot1c. and th1nk1ng r gaN1ng found tiona tot'

b .em ntle $ hOUlle$ in C ,.' ada ha

been

revi w d. However. th,.

con-.ider tlona m k .1t clear th't the found tion problem 1. onlJ' one

or

many that IiI t b 01v db· ore th pr ottc

at

_building _{ba em ntl•••}