Felt and Torch on Roofing E-Book

Tim Richardson

• Herausgeber: Crowood
• Kategorie: Fachliteratur
• Sprache: Englisch

Veröffentlichungsjahr: 2014

Beschreibung

A detailed guide to installing high performance felt and torch on roofs, for both DIY enthusiasts and professional roofers. From safety precautions, to the tips and tricks to keep a flat roof water-tight for many years, Felt and Torch on Roofing will teach the novice how to successfully complete their first felt roof to a high standard, and provide the professional with new techniques to undertaking the best quality work on felt and torch on roofing. With step-by-step guidance and photographs throughout, the book covers selecting the felt, tools and fixings, and guidance on which materials comply with building regulations; insulation guidelines and how to install and torch the felt; alternative processes for detailing and new techniques for welding, to ensure a perfect welding bead is obtained throughout the roof; cutting and forming welted drips, and new methods for sealing internal and external corners; penetrations and protrusions, detailing internal and external arcs and making repairs to the roof. Fully illustrated with 218 colour photographs.

Leseprobe

FELT AND TORCH ON ROOFING

A Practical Guide

Tim Richardson

THE CROWOOD PRESS

First published in 2014 by The Crowood Press Ltd Ramsbury, Marlborough Wiltshire SN8 2HR

www.crowood.com

This e-book first published in 2014

© Tim Richardson 2014

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers.

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

ISBN 978 1 84797 694 9

Disclaimer

Safety is of the utmost importance in every aspect of roofing. The practical procedures and the tools and equipment used in installing felt roofs are potentially dangerous. Tools should be used in strict accordance with the manufacturer’s recommended procedures and current health and safety regulations. The author and publisher cannot accept responsibility for any accident or injury caused by following the advice given in this book.

All photos by Tim Richardson

CONTENTS

PREFACE

INTRODUCTION

CHAPTER ONE: PREPARATION

CHAPTER TWO: FIXINGS, FIRRINGS AND FINISHING

CHAPTER THREE: MATERIALS

CHAPTER FOUR: QUOTING FOR JOBS

CHAPTER FIVE: WELDING AND SEALING

CHAPTER SIX: CUTTING AND FORMING WELTED DRIPS

CHAPTER SEVEN: INTERNAL CORNERS

CHAPTER EIGHT: EXTERNAL CORNERS

CHAPTER NINE: PENETRATIONS AND PROTRUSIONS

CHAPTER TEN: OUTLETS

CHAPTER ELEVEN: DETAILING INTERNAL AND EXTERNAL ARCS

CHAPTER TWELVE: CONCRETE AND BOX GUTTERS

CHAPTER THIRTEEN: METHOD OF WORK

CHAPTER FOURTEEN: REPAIRS

CHAPTER FIFTEEN: LEAD WORK AND CHASING

CHAPTER SIXTEEN: PRACTICE, PERSONALIZING AND PRIDE

GLOSSARY

FURTHER READING

INDEX

PREFACE

I started my roofing career with roofers whom I hold in the highest regard. They were also a very popular choice with other tradesmen and contract managers alike because of their attention to detail, immense knowledge, skill and faultless work. In my opinion, they were some of the best roofers and cladders in the industry. They instilled in me the knowledge, expertise and pride needed to complete any job to a high standard. While working with them I realized that pride is an essential trait for a successful roofer and I can assure you the roofers that did not take pride in their work are almost certainly not roofers today. Every job, without exception, should be completed with satisfaction – for the roofer as well as the customer.

Torch on felt roofing is a particular roofing discipline that most homeowners or builders will avoid like the plague. The reasons for this seem to be due to a lack of knowledge in the system which, given the limited information available, either online or in books, regarding the installation of these systems, is quite understandable. This book has been written to address this problem, using the knowledge of single ply systems in all areas of the detail work, which provides a much better seal to all areas of a torch on felt roof.

Many torch on felt roofers do not know about single ply techniques and may be quick to brush them off as inappropriate or not the traditional way to do things. These roofers are most probably very good at what they do, but may also be the same roofers who can’t seal tricky areas with the traditional methods and are probably too old and too proud to be taught new tricks. For everyone else, this book will provide all the information required to install a whole new roof, regardless of all tricky detail areas.

After reading this book, builders will be completing their own torch on felt roofs instead of subbing work out to a roofing firm and homeowners will be doing the same. The DIY enthusiast will be in his or her element and may even take to torch on felt roofing as a main trade. This book will save money for some, make money for others and educate all.

As a roofer I have been extremely privileged to work in different countries with different roofers installing many different systems, taking the best methods from each to compile into the perfect overall method of installation. I would like to thank the many roofers I worked with in the early days who inspired me, with a special thank you to Tony Plumbley and especially Alan Sorrell (Bullet), without whom the invaluable knowledge and conscientiousness that will hopefully be passed onto others through this book would not have been attained.

I’d like to thank Paul Hoenes for the initial inspiration to write this book. Michael D’Amore, John Patrick, Chris Holt, Glenn Kingston, Ryan Moss and Russell Thomas for help with the photographs and Matt, Ben and Alice Richardson for the knowledge, resourcing and support offered throughout. A very special thank you also goes to Martyn Barry and Sylvia Kindrachuck whose help and support will not be forgotten.

This book is dedicated to Gemma, Jessica and Cadie.

INTRODUCTION

This book is a detailed guide to installing a high performance torch on, built-up felt roof for either a DIY project at home, or for those who wish to make a living from installing felt roofs. It will also benefit current felt roofers by showing an alternative, failsafe process for detailing, while explaining new techniques for welding which will ensure a perfect welding bead is obtained throughout the roof.

There is not much information available for this particular roofing discipline. An online search gives a good picture of how to do the basics, but the more intricate detailing and how to overcome the main problem areas in felt roofing do not seem to be covered. This book will explain all, from the safety precautions to take, to the tips and tricks to keep your flat roof watertight for many years.

Torch on felt roofing systems have been around for a very long time and have been the flat roof covering of choice for most people, as when a flat roof needs replacing, homeowners tend to replace their system using a ‘like for like’ attitude. With this in mind, it is safe to say that there will always be a demand for felt roofs. If the installation techniques are followed in this book, any reader can successfully seal their own roof, or run a flat roofing business using high performance torch on felt and be able to deal with any detailing problems a flat roof can throw at you.

You will learn many tips and tricks from reading this book that most felt roofers do not want you to know, or do not know themselves. This book will teach different methods for sealing internal and external corners which steer away from the orthodox felt roof applications. These techniques allow a novice to complete their first felt roof to a high standard and, after some practice, the quality of work will be better than the professionals.

There are issues which are not thoroughly covered in this book, which regard to the technical specifications of flat roofs, insulation and building regulations. As a homeowner undertaking a DIY project, or for the odd torch on flat roof here and there, these issues do not necessarily need to be addressed in their entirety. However, for a more serious objective, or in preparation for a flat roofing business, these regulations should be noted and put into practice. Further information and regulation codes and titles are provided in the further reading chapter at the back of the book.

Before you start any flat roof, please take the time to get to know the materials and equipment you are going to use. An hour’s trial on a small mock-up roof would suffice, just remember to include any aspects of detail you are likely to come across on the actual job. The photos taken in this book have been, in some instances, simulated situations on mock roofs to represent most aspects of detailing.

The views and techniques expressed in this book are for guidance purposes. Although this book contains the correct information at the time of going to print in regards to the code of practice in installing felt roofs, it should in no way be used as a specification or quoted as such. Remember, these processes are a guide to an initial roof, and once you have found your way of working, there are not really any hard and fast rules, just that the roof has to keep out water, and look good to the eye, especially if the roof is a showpiece or in a position to be viewed by the homeowner on a regular basis.

GENERAL

The gas burner and hose used to install a torch on roof must be of a correct specification: for safety, the hose should be a minimum of 3m long and the propane bottle should be fitted with a regulator which controls the supply of gas to the hose and torch. Torch on roofing is usually a system comprising of three layers in a built-up application, however, it can also be installed in a one layer system when re-covering asphalt or an existing built-up felt system with a sound top layer. When a torch on roof is installed and laid in the form of a cap sheet, it should be continuously bonded to the underlying layer. The torching technique should replicate the process of a continuously bonded layer of a pour and roll system with hot bitumen. With this in mind, when torching any rolls of felt to a roof, the heat which is applied should be enough to create a pool of molten bitumen beneath the roll on application.

The flame from the torch should be aimed towards the ‘v’ created between the roll of felt and the underlying layer.

The hard and fast rules to follow when installing a torch on felt roof are as follows:

•

The finished felt of the final layer must be made weather tight to cover all eventualities including: rain, snow, ice and dead and imposed loads.

•

The finishing layer must always terminate at a point at least 150mm above the final roof deck height, to protect against rainwater splashing onto the surface of the roof. This height should be maintained at all parapets, abutments and door openings.

•

Wherever rainwater is allowed to run off the roof, into a gutter or even over edge checks, the turndown of the felt should be a minimum of 50mm.

•

There should be a minimum fall to a gutter edge or outlet on a flat roof of 1:80, but this minimum fall should be increased wherever practicable at the design or quoting stage.

•

Rainwater should not be allowed to pond on a roof’s surface. Ponding promotes moss growth and raises complications in winter months due to the water freezing, which will place stress upon the layers of felt.

•

At any position on the roof where a service or fixture may impede with rainwater run-off, design falls should be adjusted or crickets should be cut from insulation boards to divert rainwater to either side. Crickets can also be mitred to create cross falls if required.

•

Insulation must be added to a flat roof above any habitable space to conform to part L1 and L2 of the building regulations (England).

•

Larger roofs may require gaps, which should coincide with those in any surrounding walls to allow for movement alleviating structural, thermal and moisture stresses.

Whether rolls of felt are installed as single layer systems as an overlay to an existing asphalt roof, a built-up felt roof, or for an underlay sheet in an inverted roof design, the types of bonding of felt roof systems differentiate when the substrate is taken into account. If there is insulation on the roof deck to form a warm roof, the bond applied can be partial, in spots or strips on the underlay, and a full bond on the top layer which is the cap sheet. This will allow building movement to occur, which will be increased in the application of a warm roof due to the increased differing temperatures. In reality most roof decks are considered unacceptable for a direct torching method, so it is recommended that a layer of felt which is suitable for direct torching is fixed to the substrate with nails or a bitumen pour and roll system prior to torching.

Insulation must be designed for the use of torched applications, again if the insulation is not designed for torched applications, an underlay may be bitumen bonded to the insulation surface to accommodate the torched layers above. If there is any material used as a substrate made from sheet timber, the fire characteristics of such substrates require a mechanically fixed perforated underlay below the two top layers of felt, which should be fully bonded. The perforated underlay must be fixed with large clout headed nails across the full sheet. A bead of bitumen must always be seen extruding from the edge of any roll after installation, to ensure a good seal has been made throughout the roof. This is a rule that must be followed for all layers except the perforated underlay, which is left unsealed.

There are two main techniques of roll layout in a built-up felt roof system, these are:

Torching a roll of felt into a molten bitumen puddle.

SIDE ROLL

A side roll layout will entail any detail work on upstands to be installed at the sides of the roll.

END ROLL

An end roll layout will entail any detail work on upstands to be installed at the ends of the roll.

For any pitches greater than five degrees, a section of the cap sheet of any torched on layer must be adequately and securely fixed at its highest point along the top of the roll.

The equipment used to install a torch on felt roof should be appropriate to the job. When a gas burner is used, a regulator should always be installed to the gas bottle and the torch itself should have a stand to allow it to rest onto the roof surface without any danger or damage. Torches for burners can be found with either a single candle, or multiple candles. The trigger should also return the flame to yellow instead of blue, to aid visibility when placed on the roof.

Gas torch emitting pilot flame.

Propane burner and gas torch with a 3m hose and regulator.

CHAPTER ONE

PREPARATION

HEALTH AND SAFETY

Now I know what many of you are thinking: ‘Here’s the section about fire being hot, the diagram of a knife showing which end is sharp and how not to kill yourself by jumping off a roof.’ In all trades there are standard health and safety issues that are inherent in any type of construction and maintenance jobs. With torch on felt roofing, however, there are not just these standard dangers, but the added hazards which come with working at height, using scalding hot materials and naked flames, so please do take note.