Time study on floor and foundation system, NHBA Mark VI experimental project

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Technical Note (National Research Council of Canada. Division of Building

Research), 1969-04-01

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Time study on floor and foundation system, NHBA Mark VI

experimental project

Crocker, C. R.

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NATIONAL RESEARCH COUNCIL OF CANADA

No .

APPROyED BY NBH CHECKED BY

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C. R. Crocker

PREPARED BY

.

.

April 1969

PREPARED FOR _{NHBA Technical Research Com.m.ittee}

SUBJECT _{Tllv1E STUDY ON FLOOR AND FOUNDATION SYSTEM, NHBA}

MARK VI EXPERIMENTAL PROJECT.

In the sum.m.er and fall of 1968, a house was constructed in Kitchener, Ontario (Figure 1) under the auspice s of the National

House Builders Association. This house was the latest in a series

of experim.ental houses constructed by NHBA and is known as the Mark VI research project.

Experim.ental features incorporated in this house included a precast concrete footing and foundation system. (Figures 2 and 3)

and a sheet steel floor joist system. (Figures 4 and 5). At the

request of the NHBA Technical Research Com.m.ittee, the Division of Building Research agreed to undertake a tim.e study on these

features in the Mark VI house. The observations in this study and

the com.pilation of results were undertaken by Mr. R. T. Sum.i. Work activity was sam.pled at

the foundation and floor joist stages. attem.pted.

1 -m.inute inte rvals throughout No rating of work effort was

It m.ust be stres sed that this study was not intended to be an

econom.ic evaluation of the se system.s. As will be explained later,

labour tim.es on a one-of-a-kind house such as this usually do not provide data that can be directly projected to apply to the labour tim.e one m.ay anticipate on a repeated system..

2

-No reliable data were provided to assess adequately the unit ITlaterial cost of the foundation panels, footings, or the sheet steel joist systeITl. These unit costs will probably be the single ITlost

iITlportant factor in deterITlining the econoITlic potentials of the systeITl relative to usual construction systeITls.

SEQUENCE OF EVENTS

The sequence of events during the erection of the baseITlent was as follows:

a. Stake out the footings

b. Prepare and place sand-ceITlent bedding for footings c. Place and level footings

d. Erect and secure wall panels e. Align walls and tighten fasteners f. Caulk vertical joints

g. Grout horizontal joint between footing and panel.

The placing of the floor joists and subfloor proceded as follows: a. Mark location of joists

b. Install hangers c. Install joists

d. Apply plywood subfloor to joists.

SCOPE OF STUDY

Observations at 1-ITlinute intervals were ITlade during the erection of the baseITlent footings and baseITlent wall panels. They were also ITlade during the installation of the first and second storey floor joists, and while the subfloor, the exte rior wall sand inte rior partitions of the fir st floor we re being fitted.

RESULTS

The results of the observations are given in Table

1.

The total tiITle taken to erect the baseITlent was 3092 ITlan-ITlinutes. In addition, 410 ITlan-ITlinutes were taken to install baseITlent window fraITles, baseITlent colUITlns and the baseITlent beaITl.

The total tiITle taken to install the joists on the first floor was 528 ITlan-ITlinutes; on the second floor 578 ITlan-ITlinutes. The placing of the

3 -DISCUSSION

The times recorded for the operations that were observed were influenced by the following factors.

a. This was a one -of -a-kind project.

b. The workmen had no previous experience with the

erection of precast footings and basement wall panels.

c. The workmen had limited or no experience with steel

joist installation.

d. Site operations were inadequately planned.

e. Photographers and visitors caused numerous

interruptions.

£. Work crews were too large for some operations.

All of these factors increase labour time. A marked reduction in

the times recorded for the basement and floor joist installation would be expected in a multiple continuing housing project using experienced workmen with proper supervision.

An estimate (by R. E. Platts and R. T. Sumi) of the labour time

under optimum conditions for the experimental aspects of the MK VI

House was made and compared with similar observed operations of the

MK V House. (l)

Operation

MK VI

Site Labour

MK V Stake out and place

footings and column pads, erect and complete foundation walls.

Time per lineal foot of foundation wall.

Time per square foot of foundation wall.

Install hangers and steel joists on ground floor.

Install sill plate,

floor joists and strapping. Time per square foot of floor area. 800 man-minutes

7.9

Figure 1 View of Completed House

Figure 3 Lifting Precast Wall Panels into place with Truck Mounted Crane

Figure 5 First Floor Steel Joists Supported on Foundation Wall by Steel Joist Hangers

e

TABlE I

e

SOM! LABOUR REQUIREMENTS liN MAN-MINUTESI FOR THE MARK VI IRECORO!O VALUESI

e

..

Stake Out And Carry Mix& Mix& Mark or Po sitlon I n stall and Truck-crane

Place Footings Mati s or Place level Measure &Align Tighten Operating MIscellaneous I die Total

&Column Pads Equipment Mortar Footi ng Footings Bolts

&Erection of Bed Base &W.lls Foundation Walls

208 69 106 14 343 244 319 195 859 2351

Mix

Caulk and Carry Mix Place Dry Caulking Cement Point load Miscellaneous I die Total

Patch Mati s or Caulking Tubular IBy Gun) Paste and Caulked Caulking

Foundation Equipment Caulking Patching JOI nts Gun Walls

20 54 46 29 36 42 59 384

49 49

Grout Carry Mix Place& CII mb Clean Miscellaneous I die Total

Footings and Matis or Grout Trowel ladder and Fix

Found.tion Equipment Grouting Mixer

Walls ₁₁₄

86 28 96 2 12 13 351

I n stall Carry Mix Trowel In st. II or CII mb Miscellaneous I die Tot.1

Basement Matis or Epoxy Epoxy on Position ladder

Wi ndow Equipment Frames Frame

Frames

20 10 9 22 4 ₁₃ 13 91

I n stall Carry Move 0 r Adjust load and Mark or Miscellaneous I die Total

Basemen1 Mati s or Pisition Post Shool Measure

Columns Equipment Columns level Ramset

15 11 \I 4 I I 13 76

Carry Move or Assemble Mark or load and ell mb

I n stall or Remove Miscellaneous I die Total

Basement Mati s or Po sition Temporary Measure Shoot ladder

Beam Equipment 8eam Braces Ramset

19 65 14 \I 3 5 2 124 243

I n stall Carry Position Position Mark or Loosen and load and CII mb

Tighten Miscellaneous Idl e Total

Gro u nd Mati s or Jol sts Joi sts Measu re Shoot ladder

Floor Equipment Hangers _{Wall P.nels}Foundation R.mset

Joi sts

76 32 10 29 55 10 7 ₂₆ 283 528

I n stall Carry Nail Cut Mark or Position Check Climb Miscellaneous I die Total

Ground Mati s or IS.w) Measure Subfloorlng level ladder

Floor Equipment

Subtloorl ng

89 87 \I 27 43 5 3 34 301 600

Erect 1st storey Carry Nail Cut Mark or Move or Assemble_{or Remove} Climb _{Miscellaneous I die} Total

Exterior Walls Matis or (Saw) Measure Position _Temporary ladder

and 8earing Equipment Walls

Partition Braces

32 44 4 36 92 10 3 4 100 325

I n stall Carry Po sitlon Temporary Mark or Place and lo.d and Cii mb _{MIscellaneous I die Tot.1}

2nd Storey Matis or Joi sts and Nailing Measure Tighten 5 hoot ladder

Floor Equipment Header s of Joi sts Bolts Ramset

Jol sts