System contractors in Europe lead the way in multi-family housing

Publisher’s version / Version de l'éditeur:

Engineering and Contract Record, 81, pp. 54-59, 1968-02

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

This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur.

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

System contractors in Europe lead the way in multi-family housing

Platts, R. E.

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=d5e98584-5b96-4f8d-8ae8-0fa0530afc83

https://publications-cnrc.canada.ca/fra/voir/objet/?id=d5e98584-5b96-4f8d-8ae8-0fa0530afc83

""::X --?

Way in Multi-Family

H

;"iiE'ufifft^G

#g slefc

Repr-inted ftorn Engineering cLnd Contract Recorrl, Vol. 81, Feb. 1968, p. 54-59 Technical Paper No. 273 of the Division of Building Research,

National Research Council of Canada. Ottawa

NRC 10069

-z .,' --. -1 ( .t / ^t

.,-, d' *. v / \-2

LES ENTREPRENEURS EN CONSTRUCTION INDUSTRIALISIiE MONTRENT LA VOIE DANS LE DO\,{AINE DE L'HABITATION

SO]\4N{AIRE

La controverse soulev6e par l'opposition entre les m6thodes traditionnelles de con-struction et les systdmes industrialis6s s'est maintenant apais6e dans une grande partie de l'Europe septentrionale. Les d6cisions ont 6t6 prises, la machine de production a 6t6 constitu6e et elle fonotionne. Des logements urbains de haute qualit6 sont maintenant construits, et la main-d'oeuvre par logement s'abaisse jusqu'i 500 heures d'ouvrier, dont la moiti6 est n6cessaire ) l'usine et I'autre moiti6 sur chantier. Une 6tude des principales systdmes industrialis6s a 6t6 nren6e i bien de septembre 1966 i september 1967, en vue de d6couvrir les difficult6s et les possibilit6s de leur application dans le contexte canadien. Les diff6rentes m6thodes sont d6crites bridvement. Ce sont les m6thodes de pr6cou-lage complet du b6ton, appliqu6es par Jespersen au Danemark, Larsen-Nielsen au Danemark, Skarne en Sudde, Wates en Grande-Bretagne; I'emploi de profil6s et de panneaux de mat6riaux l6gers, appliqu6 par 5M, SFl, Cubbits en Grande-Bretagne; les panneaux de b6ton cellulaire, employ6s par Salemstaden-Siporex, en Suide. L'auteur donne une liste d'autres 6tudes de systimes, et examine cer-taines cons6quences de la construction compldte en 6l6ments pr6fabriques.

crsTt / tcrsT

use of tower or climbing cranes. Prefabrication of walls and total systems is becoming much more common.

System Contractors in Europe Lead

the Way in Multi-Family Housing

by R. E. PLATTS

The growing appreciation of the advantages of factory production, combined with the recent marked increase in multi-family housing in Canada, have created an upsurge of interest in the industrial-ized systems of housing developed in Europe. There, the population expansion and the rush to urban centres created extreme pressures for multi-family housing production, in the face of a scarcity of ffeld labour. N{uch of the demand pattern is beginning to be repeated here.

To assess the potential of such system approaches for Canadian use, the Division of Building Research of the National Research Council of Canada

ar-Mr. Platts is a Research Officer with NRC's Division of Building Research. He has just returned from a year in Europe, where he studied new techniques for "factory assembly'' of building units.

ranged for the author to be based in Europe for twelve months of field studies of leading system projects, beginning in September 1966. With excel-lent cooperation from the contractors sponsoring the systems, the ffeld work yielded a general assess-ment of the technical design, factory production and field erection fow, servicing, ffnishing and the final product.

With scores of building systems in Europe, the difficult initial task in devising a workable ffeld study program was to limit the number for study. The selection was necessarily somewhat arbitrary, based on an assessment of the svstems as thev related not only to the known Canadian conditiorx of climate, distances, and present industry strucfures, but also to assumed long-term trends. The chosen systems exhibited most or all of the following attributes: large projects underway at or near full-fow produc-tion in both factory and ffeld; producproduc-tion, erecproduc-tion and ffnal performance all designed for cold climates;

high factory content in the main system structure; high factory content and rationalization in the serv-icing and ftnishing; a minimum of wet in-situ work or other processes demanding much site labour or protection from weather; final results yielding ameni-ties and general qualiameni-ties comparable with North American housing.

The most suitable projects for study were found to be nearly all in Northern Europe, particularly in Scandinavia and the United Kingdom. In some cases a proprietary system is found in use at different levels of development in various countries and projects. (Main studies are noted overleaf.)

Augmenting the above studies, ffeld reviews served to fill in the more complete picture of notable system developments. Among these were further large panel concrete projects: the Hungarian system near Budapest, Vam in Holland, Dura Coignet in Holland, Reema in England, Skanska Cementgiute-riet's "Angle Element" and "Heart" in Sweden, and Puolimatka and Polar in Finland. The unique Jack-block process was observed in Holland. Finally, where time permitted, advanced wood component housing was reviewed in Norway, Sweden, Finland, Germany and Holland.

Parts of the urban housing production scene in Northern Europe-particularly Scandinavia-can be taken as physical models applicable to Canadian conditions both as they exist and are forecast. Such models are applicable at least as they concern so many dwellings for so many people within certain geographical areas.

For example, the island of Zealand with its main city Copenhagen shelters over I million people, most of them caught up in the extreme urbanization move-ments of the past few decades. This market absorbs over 10,000 dwellings per year, and it is reported that about 60c/o of these are produced in true indus-trialized building systems by a very few companies. At present, there are perhaps four "Zealand" pockets of population in Canada, and in the foresee-able future there may be six or seven. Already, indi-vidual projects of housing in Canada are often as large as in Europe. The political-economic attitudes in much of Europe favour more effective pre-plan-ning, national performance codes, standardization, and encouragement of market continuity and the rational use of land than is the case in Canadar all of this is conducive to proper system building growth. Some of this pattern too is beginning to repeat here as the housing pressure grows. At the same time, many of the technical developments within the northern European systems represent useful advances now, independently of volume or standardization.

At this time the systems enjoying a continuity of success are large-panel concrete. Perhaps the single reason for this is simplicity: the one low-cost ma-terial fills the functions of structure, ffre and sound resistance, and ffnish to form buildings quickly with a few large parts. The flow of production-erection

can be remarkably smooth and simple. The site be-comes in effect the assemblyJine extension of the factorv. no matter lrow distant the one from the

other. Recently, dry assembly methods have been combined with quick installation of heating to allow smooth construction throughout the winter. While the position of these advanced precast structures seems unquestioned, there is something of a trend arvay from precast exterior walls toward wood frame and other light panels in such structures, regardless of the height of the buililing.

A fully effective building system requires the in-tegrated efforts of designers, contractors and sup-pliers, as is perhaps best illustrated in Scandinavia. This lesson is emphasized at present in some proiects in the U.K., (other than the major undertakings listed previously) where the supplier industries are not yet a reliable source of complete interior com-ponents. Interiors and services are then far from being "systems", and yet these two areas form the biggest part of the total building job. The Scandi-navian building scene now includes a surprising degree of precision and preffnishing of all parts (structural. exterior and interior) and a high utiliza-ilon of complete cores and "harrresses" foi most of the servicing job. Some prefinished, moveable parti-tions from country-wide suppliers are incorporated into the accurate precast structures at low cost.

Productivity can be quite high: the labour re-quirement for a three-bedroom dwelling unit is said to be as Iow as 500 man-hours including both factory and site work, even where technical design and ffnal qtrality are well above typical apartment construc-tions in North America. More commonly the leading systems entail about 800 man-hours. Meaningful comparisons are not easy. These production ffgures start rvith the sand and gravel (one would have to include such things as the labour in manufacturing bricks to compare traditional building) but do not always include cabinetry or some service sub-assem-blies. Certainly, the high productivity and quality seen on these advanced projects is due largely to thorough job management in factory and ffeld.

The system projects allow faster turn-over and better utilization of money since the overall con-struction time can be quite short. As an example, the first apartment on a large project may be rented about six months after the site start, and comple-tions follow at a rate of 3 a day, without overtime work. At present, the ffrst costs are said to be closely comparable rvith traditional building in the same countries, with the systems producing high-rise build-ings at signiftcantly lower cost, and low-rise housing at slightly lower to somewhat higher costs than tra-ditional. In many such cases this reflects the unfortu-nate partial use of systems factories. It is of interest to note a trend back to lower housing in Scandinavia and the U.K., despite the increasing urban pressures for high-density land use.

The leading developers of steel system building are concentrating their efforts on systems with larger and fewer parts and simplified fire protection, sound control, and general "make good" operations. Flexi-bility of spans and layouts and the full utilization of steel's precision are evident in much of the leading work.

invest-ment in plant that is low as opposed to the capital expenditure in manufacturing industries but some-rvhat higher than in traditional building operations. An efficient permanent plant of mediurn mechaniza-tion might cost over $500,000 for a producmechaniza-tion capa-city of 300 dwellings a year; over $1,200,000 for 1,000 a year (both on single shift capacity). The apparent trend in Europe toward vertical battery plant would be stlengthened by climate factors in Canada, The cost of site mechanization to comple-ment the larger factory comple-mentioned above-to erect 1,000 dwellings a year-might be over 9600,000. In

this aspect, it is useful to note the trend in much of Northern Europe torvard crawler'-boom cranes and mobile boom cranes and away from the less flexible towel and rail-tower cranes.

Considering the investment in plant and the amount of thought in planning and integrating de-sign r,vith production in such organized system fow -quite _{new to much of traditional building-the} ploper evolution of multi-farnily urban house pro-duction in Canada could well involve cooperative arlangements with the pioneering European devel-opers. There is much to learn.

Systems approach for precast concrete

!.*

COVER

PICTURE

Sponsor and consultant on this systern: Larsen and Neilsen Consultor A/S, Copenhagen. Denmark. The U.K, sponsor and contractor is Taylor Woodrow-Anglian Limited. Projects were studied in London and Newcastle (up to 16 storeys), the factory in Newcastle, and the proiect at Tibberupparken, near Elsinore, Denmark was briefy reviewed (3-storey blocks).

"LN" is an original example of the "Danish type" of large panel concrete system, featuring precise panels, The large-panel precast concrete systems studied have their structural crosswalls, foors, elevator cores, and shear walls formed entirely from large panels (above left, Wates Ltd.). The buildings are essen-tially gravity structures. The foors are tied with steel bars in the joints (no site welding) to function as full horizontal diaphragms. Level adjustments are done using cast-in-panel levelling bolts (acting also

as locating dowels) in several systems, while shims are used in others. Joints are then grouted or "dry packed". Following limited interior patching, wall-papers and textured paints are used to ffnish the concrete panel walls and ceilings, An important fea-ture is the complete thermal protection of the entire structure, proiections, (above right, Taylor Woodrow Ltd.) and the enclosed living space.

narrow joints, dry assembly, and "open rain screen" ex-terior joints. Foundations may be of precast panels. Elec-trical and other services are run over the floor panels on the job and covered later by floating in-situ screeds or wood foors. Bathrooms are produccd as ffnished room units. Exterior precast walls are normally of free "sand-wich" design, with a structural inner leaf supporting a thinner outer leaf which remains free to expand and contract, with 4 in. of foam polystytene in between. Light facade panels are also used. The concrete com-ponents are produced in central plants of medium-high mechanization, featuring movable fat moulds, mechan-ical concrete placers, and retractable mandrels for the tubular core floor panels.

System co-sponsors and consult-ants were Jedpersen and Sons and P. E. Malmstrom A/S, Copenhagen, Denmark. The U,K. sponsor and con-tractor was John Laing Construction Limited, Manchester. Projects and fac-tories were studied at Bjuv, Sweden, and Manchester (3-storey blocks).

The system is similar in history and type to the Larsen and Neilsen sys-tem, but features more emphasis on standard foor panels and a modular range of crosswall panels. Except on large standardized projects, Jespersen relies on service harnesses and partial kitchen and bath cores rather than on complete room units. Exterior walls

Projects involving 2l-storey blocks were studied at Waltham Forest and Lambeth, London, Sponsor and con-tractor was Wates Ltd.

Cast-in electrical conduit is used with baseboard circuits. Direct ffnish-ing of precast foors is effected with a felt-back sheet vinyl. Wood window-walls enclose most of the building (precast balconies help provide ffre protection). Concrete sandwich fac-ades are also used where desired. Pro-duction is carried out in unique on-site plants of medium mechanization, Heated stationary fat moulds produce the foors; vertical batteries, the cross-walls. The casting area can be pro-tected by movable shelters mounted on rails (left).

are often light panels utilizing the "open rain screen" principle through-out, with spaced and vented outer leaves, These may be used in com-bination with free sandwich panels (left). Production of concrete com-ponents is done in highly mechanized central plants noted for their foor panel production line, with its semi-automated progression of fat moulds through all stages of setting-up, con-crete placing, tubular core forming, curing, and striking. Crosswall panels are produced in vertical batteries in-corporating mechanization of concrete placing and other operatiorls in the factory.

Sponsor and contractor here was Ohlsson and Skarne AB and consultants were Skarne Internationella AB Stockholm, Sweden. The U.K. sponsor and contrac-tor was Crudens Limited, Edinburgh and London. Proiects were studied in Stockholm and Newcastle (3-storey blocks); the factory was also studied in Newcastle.

The "S 66" system employs precise foor panels of longer spans than in normal European practice, with interior precast columns and load-bearing sand-wich outer wall panels, to gain cornpletely open

dwelling space. Panel surfaces are especially fat be-cause of vertical battery production' and floors, walls and ceilings are directly ffnished before any parti-tions are placed (above left). A preffnished partition system of rnodular panels can be run to suit any lay-out, and is fully demountable. Cast-in services are largely avoided (except in one-piece bathroom floors): panel chases and joints accept the electrical harnesses, while heavier services are run in the central core walls. Plant (above) features special vertical batteries for both walls and foor panels.

Light and dty systems

The precast systems described earlier can be used for both low- and high-rise structures, with little modification. The following "light and dry" systems tend to be designed for given heights, but all include approaches usable for a range of building heights.

V

This system was devised for the New Town project, Salemstaden, near Stockholm: 1- and 2-storey row

hous-ing. Developed by Internationella Siporex and others

for the client and builders, the City of Stockholm and its housing company, AB Svenska Bostader, with Anders Dios AB as the prime contractor.

Precise Siporex panels 60 cm wide are assembled against thin gaskets with simple butt joints to form all floors and walls and most partitions (below). Panel walls are simply twinned to form party walls. ("Party wall" is used to

denote walls separating dwelling units, irrelative of

ownership or tenancy). Wall exteriors are factory finish-ed with a texturfinish-ed acrylic plastic coating. Interiors are wallpapered or painted; ceilings are of stretched vinyl film. Roofs are assembled from large prefabricated sec-tions of wood truss construction complete with ceilings, insulation, and prime asphalt roofing. Precast grade beam foundations enclose service trenches carrying all heating from a central heating plant.

A

"5M" concept was developed by the Ministry of Housing and Local Gov-ernment, U.K. Proiect studied was at

Harlow New Town: 2-storey row

housing. Contractor was Taylor

Woodrow-Anglian Co. Ltd.

The system is derived from the fa-mous Clasp school system, using a light steel and wood frame with wood panel inffll, all centered on a gfid of "5M" (20-in.) (above). A special con-crete grade slab is cast in situ. Double leaves of laminated gypsum wallboard form the party waII. This and pre-formed asbestos-cement boxing forms the ftre protection for the steel. Fram-ing and internal layout are almost completely modular.

Developer and contractor here was Cubitts Construction Systems Limited. London, U.K. Proiects studied were at Maidenhead.

Four-storey bolted steel framework is erected on concrete footings pocket-ed under a grade slab, and levellpocket-ed and plumbed as one assembly. Inffll walls and foors are largely of wood frame and stressed skin constructions. Double leaves of S-in. thick light-weight concrete panels form the party walls (left), and the foors separating dwelling units are made from pre-stressed concrete I-beams and block inffll. The party waII and asbestos-cement covers form the ffre protection for the steel. Roofs are of wood trusses assembled in whole-house sec-tions on the ground. Interior parti-tions are sandwich panels of gypsum dry-wall and paper honeycomb.

"SFl" sponsor arrd developer was The Greater London Council, U.K., with the fndulex Engineering and Red-path Brown Companies. Project studied was at Walter-ton Road, City of Westminster: 2l-storey tower blocks. A steel frame of unusual precision forms ftrst a central elevator core encased in in-situ concrete to impart the prime stability. Load-bearing exterior wall assemblies 3 storeys high consist of composite panels of moulded ffber glass-plastic exterior on lightweight concrete, which are mounted in sets of six on a precise steel frame (left). Floors are precast concrete panels on steel beams. The steel is ffre protected with sprayed asbestos. Interiors are fftted out with sandwich panel partitions. Party walls are of double leaves of solid gypsum panels augmented with gypsum board. Some of the electrical services are cast in the foor panels, while a gap around the foor perimeter forms a service distribution space, later fflled with con-crete (above).