Ty Unnos Welsh Timber Board Development APPROVAL. Thomas Martin. Purpose of issue:

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1 Purpose of issue: APPROVAL Document title: Document revision: Issue date: 28 Sep Ty Unnos Welsh Timber Board Development

2 Purpose of issue: APPROVAL Document title: Report Ref: Created 28/09/2011 Author: Ian Jones Checked: Signed: Signed Thomas Martin Document revision: - Issue date: 28 Sep 11 Document tracking: Revision: Description: Issued by: Date: Checked: Ty Unnos Welsh Timber Board Development This printing work may not be reproduced by any means without prior written permission of Burroughs and it may not be used without such permission for any work other than the one for which it was intended.

3 Contents Executive Summary / Background 1.0 Introduction 2.0 Cross Laminated Timber 2.1 Home Grown Cross Laminated Timber 2.2 Multi-ply Boarding System 2.3 Development of the Cross Laminated System 2.4 Calculation Methods 3.0 Conclusions Appendix 1 Initial Cross Laminated Panel Calculations Appendix 2 - Images Contents

4 1.0 Introduction This report presents the findings of a scoping exercise to establish the viability for the development of a home ground softwood cross laminated timber boarding system. Coed Cymru instructed Burroughs to undertake a preliminary scoping study in February This reports sets out the necessary process to develop a structural Welsh Cross Laminated board. The main aim of the report is to establish the viability of a home grown cross laminated board. 2.0 Cross Laminated Timber Cross laminated timber panels are produced by a number of manufactures across Europe and consist of dried boards which are stacked together at right angles and glued over the entirety of their surface. Panels are produced are between, three and seven boards thick depending on the structural load capacity required to supported. Typically gluing at high pressures is necessary to reduce expansion and shrinkage and provide a dimensionally stable board for use in the construction and housing markets. 2.1 Home Grown Cross Laminated Timber The approached proposed by Coed Cymru for the manufacture of a home grown system is as follows: Use home grown Spruce and Larch in the form of tongue and groove boards to form the layers of two to five ply panels Investigate other angled orientations to tune stiffness to specific uses Use common workshop technologies for the gluing of the home grown timbers to limit the set up costs and maximise future production. Use knowledge of kilning home grown timbers to control instability in timber prior to gluing. 2.2 Multi-ply Boarding System All multi-ply structural systems attempt to create a two way spanning board from a material which has a preferred span orientation. This resulting board is a compromise between strength and robustness, creating a more stable system which has lower absolute bending capacity. The limitations relating to the use of non-engineered home grown timber sections are: Stability of sections under normal site conditions. Strength of the material when compared with imported materials on a like for like basis. The number of defects which limit the strength but also the ability to grade material consistently. Each of these limitations is improved by a cross laminated timber approach and would appear to improve values of strength provided in the code for normal distribution of defects which now are in a load sharing boarded system. Page 1 of 1

5 2.3 Development of the Cross Laminated System The following will need to be investigated to develop a cross laminated system for the market and to certificate the boards for housing market: Outline the likely use for a home grown system. This is likely to consist of load bearing cross laminated walling and racking elements within domestic housing structures. Short spanning floors between home grown beams completes the system. Ceiling and roofing members could be based on more common spanning distances or similar to the principle floors. Axial loading testing to determine vertical loading capacity Flexural testing to determine spanning and defection capacity. Racking testing to determine lateral load capacity. Prior to undertaking full certification testing it would be prudent to undertake a limited amount of prototype testing on full size samples. While model testing is valid for some structural systems, due to the nature of multiply systems, the larger the sample being tested the more accurate the results. This is primarily due to the nature of defect distribution with in the test piece. 2.4 Calculation Methods An initial assessment has been undertake to review likely capacities and stiffness of the boards under different configurations (refer to appendix 1). Due to the variation in timber and likely glue line slippages it is considered that only test values be used for the design of cross laminated boarded systems. The results of the initial assessment should be considered as an upper bound on the capacities, unlikely to be exceeded in testing. 3.0 Conclusions Providing the economics can be proven the use of home grown Spruce and Larch in a cross laminated boards would appear to viable. This use for this material would improve the stability and robustness of the non-engineered sawn timber. Page 2 of 2

6 Layer Layer Layer Option 1 Appendix 1 Initial Cross Laminated Panel Calculations Layer Layer Layer Option 2 Layer Layer Layer Option 3 Layer Layer Layer Layer Option 1 Layer Layer Layer Layer Option 2 Layer Layer Layer Layer Option 3 Page 1 of 1

7 Layer Layer Layer Layer Layer Option 1 Layer Layer Layer Layer Layer Option 2 Layer Layer Layer Layer Layer Option 3 Page 2 of 2

8 Timber 1 Timber 2 Major Axis Bending Cap Minor Axis Bending Capacity Layer Effect of Orientation Page 3 of 3

9 Appendix 2 Images Jumbo Ply construction using thick cross laminated timber sections for floors and walls. Typical Cross laminated timber with boards at 90 degrees to each other. Page 4 of 4

10 Registered Office: 4 Radnor Court 256 Cowbridge Road East Cardiff CF5 1GZ T: F: E: admin@burroughs.co.uk Registration No: VAT Registration No: Group branches: Isle of Man and Ireland. Burroughs is the trading name of Alistair Burroughs Design Partnership Ltd. This printing work may not be reproduced by any means without prior written permission of Burroughs and it may not be used without such permission for any work other than the one for which it was intended.