What is roof pointing?March 23, 2016
Flexible pointing, or “flexi point’, is a water based polymer compound that adheres to roofing tiles and ridge caps on tile roofs in Australia. It seals the ridge cap to the standard tile or gable end. It’s main purpose is to keep moisture out thereby protecting the roofing system and underlying bedding. Having the added benefit of being flexible means it moves with the roof over time and will not crack as quickly as traditional mortar based pointing.
In the past the norm was to simply use a sand – cement based mortar to adhere ridge caps to roof tiles. The roofers of old would use a mixture of sand, aggregate and cement that would stand the test of time. Flexible pointing was introduced to enhance the longevity of this mortar. Sadly the opposite happened when the strength of flexible pointing allowed roofers to start using lower integrity bedding formulae. It became quicker and cheaper to mix a common builders cement with an everyday brick sand and rely more upon the pointing. This is what we are commonly seeing in everyday estates today where low-quality bedding is being used together with flexible pointing.
Flexible pointing is a relatively new invention in roofing products. It first came about in Australia two decades ago to address our issues with mortar based pointing prematurely cracking. Flexible pointing was first marketed by Flexitech Pty Ltd and it was quickly picked up by trade professionals alike. It is a difficult product to apply requiring a finely developed trowel skills for a smooth application finish.
The product itself has a very fast cure time. This means it must be applied quickly to ensure a smooth trowel finish. On a hot Melbourne summer day, a tradesman may have little more than ten seconds from the moment the product leaves the bucket to when the finishing pass is made. It takes about 24 hours for the product to initially cure, during this time no rain or water should make contact – where rain affects the product, especially within the first two hours of application, it will visibly loose its smooth finish leaving peaks/troughs in its thickness and reduce its effectiveness.
The minimum desired thickness is five millimetres at the top to ten millimetres at the bottom. This is a perfectly fine as the flexipoint acts as a water barrier to protect the underlying bedding. But what happens where a small part of the flexi is not very thick due to human application error? This can easily happen and it ends up exposing the bedding to moisture through premature cracking or peeling away of the flexible pointing. Had the bedding been that of 30 years ago, this may not have been such an issue. However with modern construction standards, the weak mixture of builders cement and regular brick sand, the bedding is now exposed and unable cope with the elements thereby failing and causing one of the most common roof repair scenarios we face.
We at Casey Roof Care bridge the gap between new and old. Our bedding formula comprises a higher ratio of cement to sand together with an aggregate just as they did 30 years ago. In addition we use a concrete plasticizer. All of these elements together combine to create a high strength and durable bedding compound backed by our standard 10 year guarantee. To finish it off we use a cyclone rated flexible pointing compound, applied by an experienced tradesman, backed again by a 10 year warranty.
It is not difficult or expensive to make these changes. While we may not be the cheapest in the market, you know exactly what you are getting from us. If you don’t understand what you are being quoted on, simply ask. We are available 7 days a week to take your calls and answer your questions.