After a long time some parts of the building comes off. It is advisable to use a material that will not come off after a short time of applying it. Cement is not recommended when it comes to sandstone repair. Cement traps moisture and salt when it dries. This means that the part that you have repaired will be damaged after a short while. Before you embark on the process of repairing the sand stone you should know what the cause of the damage or decay was. Most of the times the cause is of damage are trapped moisture or repair of the past that was not done in the right way.
Prepare the sand stone.
After identifying the cause of the damage the next thing is to prepare the sandstone. You should not only repair the top part of the stone. You should repair the whole portion which is destroyed. So using a toothed chisel you should cut out the part around the damaged area. This part that is cut out should not be big as it will waste more material. Remove the part that is necessary. After cutting out the part then you should clean out the hole that you have created. You can use pressure water to clear out the dust and other materials. Ensure that that place is free of dust particles and any other foreign materials before applying the mortar. The place also should be damp. Avoid putting the mortar in a place with standing water. Use sponge to clear out any standing water.
Appling the mortar.
After preparing the area to put the mortar the next thing is to apply the mortar. The mixture should be applied in a specific way. First apply 3mm of mixture from the surface. The total thickness should be about 40mm. This 40mm should not be applied at a single phase. It should be applied in 2-3 phases in each phase you should apply about 20mm. After applying 20 mm you should make a criss-cross sign. This is to assist the subsequent applications. The next application should be after 2hours. The final layer should be about 2mm from the surface. This is the portion that will be scrapped off to enable the repaired part to blend in with existing surface. After putting the final part you should wait for about 4-24 hours depending on the weather condition so as to smoothen. The process of smoothening is known as finishing.
The final part.
This process is called finishing. It is the final part in sandstone repair. It takes place 4-24 hours after the application of the final layer. This process is there so as to ensure the repaired part looks the same as with the other original part. Use a trowel, carbide or tungsten to scrap of the part. You should scarp out the part that is above the original wall so as to make it uniform. Then you should smoothen out the whole part. The places that are not level with the original surface should be filled up.
