The Typical Difficulty With All types Of Flat Roof Coverings Is That Over Time They Are Likely To Dip Or Sag In The Middle Which Allows Rainwater To Concentrate In One Place.
Rainwater Ponding
Eventually That Repeated Pressure And Collection Of Water Will Find The Smallest Point Of Weakness In The Underlying Roofing Material And Penetrate Though.Where The Roof In Question Is Aged And Has Been Poorly Maintained It Is Likely To Be Decked With Chipboard. This Should Be Replaced In All Circumstances With At Least Marine Plywood Or Alternatively WBP Plywood. Equally Important To Consider Is The Gradient Of The Flat Roof. The Flat Roof Gradient Needs To Be Set To At Least 1 In 80 Or Else Rainwater Will Not Naturally Run Off It Causing The Classic “Ponding” Weakness.
Bitumen Roofing
Historically The Majority Of Flat Roofs Were Covered With Bitumen Using A Crude Pour And Roll Method. Newer Replacement Materials Have Been Proven Over The Last 30 Years Or So, Such As EDPM ( Rubber ) And GRP ( Fiberglass ). However “Torch-On Felt” Is A Perfectly Acceptable Modern Covering Method Making Use Of A Time-Proven Material.
Torch-On Felt Method
It Remains Important To Broadly Understand The Nature Of The Three Mainstream Roof Covering Material Methods. A Simple Description Of The “Torch-On Felt” Method Would Be That It Comprises Of A Three Layer System. The First Layer Is A Vapour Control Layer Upon Which A Layer Of Reinforced Felt Of At Least Two Millimeters Sits Over It. Finally A “Cap Sheet” Of At Least 4 Millimeters Sits On The Top To Complete The Effect. Then All The Layers Are Effectively Joined Together By The Use Of A Hot Torch. Visually The “Cap Sheet” May Be In The Form Of A Plain Black Finish Or A Mineral Finish To Match The Required Building Appearance Colour.
EDPM Rubber Roofing
An EDPM Rubber Roof Is Created By Applying A Single Layer Of EDPM Material With Glue To Either A Pre-Existing Layer Of Decking If It Is Sufficiently Sound, Or Replacement Decking If Required. Some Particular Care And Skill May Be Required To Negotiate Specific Roof Details So That Joins In The Material May In Fact Be Required Particularly Around The Roof Edges And By Down pipes.
On One Hand It Does Carry The Advantage Of Being The Most Flexible Material In Response To The Elements And Change Of Season. It Is Both Tough And Durable And Generally Resistant To Downward Foot Pressure. On The Other Hand It May Not Be The Most Preferred Material To Control Risks Of Condensation In Comparison To Say “Torch-On Felt” Which Performs Better Generally In Allowing Some Air Flow. In Addition Aesthetically Its Dull Matt Grey Appearance May Not Be Particularly Appealing And May Devalue Other Aspects Of The Buildings Finish.
GRP Fibreglass Roofing
The GRP ( Fiberglass ) Roof Solution Whilst Still Mainstream Has Possibly The Smallest Quantity Of Installations Comparatively. This May In Some Part Be Attributed To The Likely Need To Fully Replace The Existing Decking With Osb Plywood To Enable Specialist Resins To Be Applied To Seal Down The Top Single Material Layer. Once Cured Over About A Six Month Or Greater Period The Initial Appearance Will Have Dulled And The Finish Is Likely To Be The Toughest Of The Three Roof Covering Types. This Solution May Trump The Others With The Quality Of Its Appearance In So Far As The Top Layer Can Be Painted To Match Any Colour But Will Not Perform As Well As Either Alternative In Respect Of Flexibility And Condensation Control Limitations.