Failing mortar can usually be attributed to a lack of carbonation of the lime within the mortar meaning that the mortar will have little if any strength.
Roof mortar crumbling.
This is generally a straightforward thing to do.
This is a beginners guide to pointing up.
Crumbling or failing mortar can be caused by a number of reasons.
If we re talking about common roofing jobs like pointing a chimney laying ridge tiles or flaunching the top of a chimney i would recommend a 3.
The roof verge will need to be rebedded with mortar.
Roof cement is primarily used to hold roof tiles hip tiles and ridge tiles securely in place it also keeps out rainwater.
This is a great concern and something that highlights the need for a better understanding about what it takes to create a long lasting and top quality mortar.
Your builder is wrong to say its fine if the mortar is crumbling away.
The fact that it is very porous means that it can hold water.
The temperature change that comes with the seasons can also mean the swell and contracting of the mortar.
This not only causes cracking but it can also cause crumbling as the mortar denigrates.
The correct mix ratio is 3 parts sand to 1 part cement this is much stronger than bricklayers use 5 1 as the cement on the roof must withstand more driving rain than a typic.
How much cement in a roof mortar mix.
At the end of 2018 there were media reports of several new build homes suffering from crumbling mortar between the bricks.
Chimneys are often positioned in exposed areas of the roof and crumbling can occur due to weathering even if other brickwork around your home is in good condition.
When the mortar on a verge crumbles or disappears then there is a risk of leaks from water being blown into the roof space.
The mix sounds ok at 4 1 if this is what he did use the problem is either the sand is to soft and maybe should have been sharper or i suspect he done it during the low temperatures we had and it has killed the mortar which i try to avoid or never used a wintermix frost proofer or covered his work up at the end of the day.
1 mix 3 parts sand to one cement.
