New dowel lam­i­nated tim­ber prod­uct to be used for struc­tural ap­pli­ca­tions

Australasian Timber - - NEWS -

STRUCTURECRAFT Builders Cor­po­ra­tion is build­ing a 50,000-square­foot, all-wood fa­cil­ity in Ab­bots­ford, B.C. to man­u­fac­ture dowel lam­i­nated tim­ber (DLT). DLT is made en­tirely from soft­wood and hard­wood with no me­tal, glue or plas­tic.

“We ex­pect the plant to be com­pleted by the end of sum­mer 2017 and the first DLT to be avail­able for sale in Jan­uary 2018,” said Lu­cas Epp, StructureCraft’s head of en­gi­neer­ing.

He said his com­pany will be the first man­u­fac­turer of DLT in North Amer­ica.

DLT pan­els have all the wood fi­bre go­ing in a sin­gle di­rec­tion and use dow­elling pat­terns in­stead of nails or lay­ers of glue.

The pan­els can be used for floor, wall and roof struc­tures.

Epp said DLT is less ex­pen­sive than glued prod­ucts to man­u­fac­ture. The bright idea to use hard­wood dow­els to con­nect soft­wood boards was con­ceived in Switzer­land in the 1990s.

To­day, there are about 20 DLT man­u­fac­tur­ers in Eu­rope, most of them in Ger­many, Aus­tria and Switzer­land.

DLT may be the most re­cent mass tim­ber prod­uct, but it joins many others al­ready on the mar­ket.

Some of them are nail lam­i­nated tim­ber (NLT), cross lam­i­nated tim­ber (CLT), glue lam­i­nated tim­ber (GLT), lam­i­nated ve­neer lum­ber and lam­i­nated strand lum­ber.

“Ar­chi­tects and struc­tural en­gi­neers are be­com­ing more fa­mil­iar with the prop­er­ties of struc­tural en­gi­neered wood,” said Jana Foit, se­nior as­so­ci­ate at Perkins+Will Ar­chi­tec­ture in Van­cou­ver.

En­gi­neered wood has ad­van­tages over steel and con­crete as a struc­tural ma­te­rial, said Foit.

“For ex­am­ple, it is faster to erect,” she said. “On the other hand, en­gi­neered wood is vul­ner­a­ble to wet weather and con­struc­tion needs to be sched­uled to mit­i­gate the ef­fects of mois­ture.”

Al­though mass tim­ber has been used in Eu­rope for decades, Canada is catch­ing up quickly, said Duane Pal­i­broda, man­ag­ing prin­ci­pal of Van­cou­ver struc­tural en­gi­neers Fast + Epp.

“We have been work­ing with mass tim­ber on projects in the Lower Main­land for sev­eral years,” Pal­i­broda said.

Ex­am­ples of Fast + Epp projects that use en­gi­neered wood in­clude the Brent­wood Sky­train Sta­tion in Burn­aby; Brig­house El­e­men­tary School in Rich­mond; the Moun­tain Equip­ment Co-op head of­fice in Van­cou­ver; and the Whistler Pub­lic Li­brary.

In ad­di­tion to Fast + Epp, and thanks in part to the B.C. Gov­ern­ment’s Wood First Ini­tia­tive, other com­pa­nies in the con­struc­tion in­dus­try are find­ing struc­tural ap­pli­ca­tions for en­gi­neered wood, said Mark Porter of As­so­ci­ated En­gi­neer­ing in Burn­aby.

“En­gi­neered wood is more sta­ble than reg­u­lar sawed lum­ber, stronger and more pre­dictable in its be­hav­iour,” he said. “One of the most re­cent en­gi­neered wood prod­ucts to be used in West­ern Canada is CLT.”

Much ink has been spilled re­cently on the use of CLT in the 18-storey Brock Com­mons stu­dent res­i­dence at the Univer­sity of BC.

“Brock Com­mons is the first mass tim­ber tower in North Amer­ica,” said Karla Fraser, se­nior project man­ager at Ur­ban One Builders CM Inc., the project’s con­struc­tion man­ager. “And it is the first time we have used CLT as a struc­tural floor plate as part of a wood tower. But it will not be the last time we use this type of build­ing ma­te­rial.”

Fraser said CLT is an eas­ier build­ing ma­te­rial to man­age through­out the con­struc­tion of a project.

“Due to its cross lam­i­na­tion it is not sus­cep­ti­ble to curl­ing when it gets wet,” Fraser said. “It is un­like NLT or GLT, which tends to curl the en­tire mem­ber when ex­posed to rain.”

Mois­ture on CLT, on the other hand, could be man­aged with fans and by re­mov­ing the water from the sur­face of the wood.

“Within a few hours of mov­ing the water off the wood, it came back to kiln-dry mois­ture read­ings,” Fraser said.

Projects such as Brock Com­mons are also note­wor­thy be­cause the use of en­gi­neered wood has been lead­ing to in­creased co-op­er­a­tion be­tween struc­tural en­gi­neers and build­ing sci­ence en­gi­neers.

“En­gi­neered wood build­ings are built quickly and some spe­cial weather pro­tec­tion is re­quired dur­ing con­struc­tion,” said Les­lie Peer, prin­ci­pal of en­gi­neers

Read Jones Christof­fersen Ltd. “This as­pect of en­gi­neered wood con­struc­tion is driven by com­puter-aided pre-man­u­fac­tur­ing of build­ing el­e­ments, which is a big change in the con­struc­tion in­dus­try and is mov­ing ahead rapidly in the wood sec­tor.”

Build­ing el­e­ments are man­u­fac­tured pre­cisely off-site and erected by small crews on site.

“Since wood is af­fected on­site by mois­ture ab­sorp­tion more than steel or con­crete is, it needs to be pro­tected dur­ing con­struc­tion,” said Peer. “That is be­hind the need for tem­po­rary pro­tec­tion and more rapid in­stal­la­tion of the build­ing fa­cade and roof.”

Dowel lam­i­nated tim­ber (DLT) is made en­tirely from soft­wood and hard­wood with no me­tal, glue or plas­tic. DLT pan­els have all the wood fi­bre go­ing in a sin­gle di­rec­tion and use dow­elling pat­terns in­stead of nails or lay­ers of glue. Photo: StructureCraft

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