Is rendering bad for brickwork?

[jonnypetrie]

I was always under the impression that rendering a brick wall was good as it protected the brick from the weather. I've saw a couple things now that are making me think. Some things I have seen are saying rendering over brickwork is bad for is as it stops the brick breathing and will result in the brick deteriorating. Could anyone let me know what's right/wrong? Related to this question, I dug a 300mm trench around the base of my house which I will fill with gravel to stop water sitting against the base of the house. I was going to paint the brickwork with a bitumen paint to seal it before I but the stone in but i'm thinking twice about it now

 

[ZUNDAP]

Are you taking about an outside wall?

Why are you contemplating having the wall rendered?

Is it a damp problem?

Generally speaking, the brick work does not need any protection, also generally speaking exterior walls only require re pointing and even then that would only be old walls.

Rendering out side can cause problems, by having cow boys do the job for one thing and if there is subsidence in your area, particularly in a mining area. The weather of course over many years will take its toll on rendering albeit some years ahead.

Rendering is a very stiff rigid material, extreme temperature fluctuations cold in winter and hot in summer, over the years will make the render expand and contract only slightly but it accumulates over the years. If small bits of render do fall off it is very difficult and some times impossible to patch up and make an invisible repair.

 

[jonnypetrie]

The house was rendered when I moved in with a roughcast render. I've had that replaced on the west wall as it come away from the bricks. What i've seen now is that this will stop the brick 'breathing' and therefore start to deteriorate them. If rendering is bad for the bricks why is it basically every house I see (west coast of scotland) has the walls rendered?

 

[ZUNDAP]

Hi Jonny, it may seem contradictory i know, but some times buildings are put up in regard to style, especially in rural area's. To build in stone is far more expensive that building in bricks. If your in an area where stone buildings are the norm, brick buildings would look an eye sore, hence the render option. They can build a house in cheap blocks and then render those, so not only is it a cheaper option than building in brick and it is easier on the eye, it fits in to the surrounding area better than brick.

Buildings put up with cost in mind in most case's.

Are you taking about an outside wall?

Why are you contemplating having the wall rendered?

Is it a damp problem?

Could you answer the questions above? It would may prove more helpful to give advice.

A good example of using cheaper material is having felt rooves, in the sixties and seventies it was all the rage, simply because it was the cheaper option. In those days you only got a 15 year guarantee, it was not quality at all. Even now, though materials have advanced technically, i think you can only get a 25 year guarantee on felt rooves. With slate your looking at a life span of 80 t0 100 years, but its far more expensive initially.

So you see that quality is rarely the builders upper most priority.

 

[jonnypetrie]

//www.diynot.com/forums/building/brick-under-render-crumbling.290926/#2118522

Here's a pic of the exterior of the house when i was getting the render removed. You can see the red bricks are crumbly. I thought this was due to water penetrating the render and the freeze/thaw action destroyed the bricks.

This is my initial post before removing the render

//www.diynot.com/forums/viewtopic.php?p=1997690#1997690

In answer to your questions:

Are you taking about an outside wall? Yes

Why are you contemplating having the wall rendered? The wall is currently rendered, I'm not worried about the bricks. I got the wall above re-rendered with a sand/cement render, I'm now worried this will cause more damage to the bricks. I think the house is rendered with a lime based render.

Is it a damp problem? Not a major problem, I have no mould on the walls, but do have a smell in the house. If we put the de-humidifier on if will take 2l out the air in a day.

 

[peterperfection]

The house was rendered when I moved in with a roughcast render. I've had that replaced on the west wall as it come away from the bricks. What i've seen now is that this will stop the brick 'breathing' and therefore start to deteriorate them. If rendering is bad for the bricks why is it basically every house I see (west coast of scotland) has the walls rendered?

Because the render blends in with the sheep.

 

[peterperfection]

Hi Jonny, it may seem contradictory i know, but some times buildings are put up in regard to style, especially in rural area's. To build in stone is far more expensive that building in bricks. If your in an area where stone buildings are the norm, brick buildings would look an eye sore, hence the render option. They can build a house in cheap blocks and then render those, so not only is it a cheaper option than building in brick and it is easier on the eye, it fits in to the surrounding area better than brick.

Buildings put up with cost in mind in most case's.

Are you taking about an outside wall?

Why are you contemplating having the wall rendered?

Is it a damp problem?

Could you answer the questions above? It would may prove more helpful to give advice.

A good example of using cheaper material is having felt rooves, in the sixties and seventies it was all the rage, simply because it was the cheaper option. In those days you only got a 15 year guarantee, it was not quality at all. Even now, though materials have advanced technically, i think you can only get a 25 year guarantee on felt rooves. With slate your looking at a life span of 80 t0 100 years, but its far more expensive initially.

So you see that quality is rarely the builders upper most priority.

Slate on side of a house looks like a abortion.