replacing bricks & cause of blown bricks

[diy_fun_uk]

Hi

some of the bricks on my outside stairs have 'blown' (hope that's the correct term!) over the past couple of years, see below. am I right to assume the entire structure is save-able i.e. hasn't reached a stage where it requires to be completely rebuilt? I'm thinking about having a go at knocking out and replacing the damaged bricks. I've never done brick work before however I'm a reasonably competent DIY'er, so do you reckon it's a task I should be able to complete?

also, am I right to assume the cause of the blown bricks is water/damp getting in behind (VERY likely through gap on top of stairs, see attached) and then expanding in cold temps? even if not the cause, I'm intending to block the gap between the slabs as well.

overall, is my approach correct? and any idea what kind of bricks they are?









thanks in advance

 

[RonnyRaygun]

They've blown because they are not frost resistant and shouldn't be used in exposed conditions. Generally non frost resistant bricks should only be used above dpc level in dwellings or elsewhere where a dpc has been used.

You can cut out and replace but the same thing will happen eventually to all the others.

You might be better off rendering over them but you will need to make sure you give a good key to the render by using well secured eml as the bricks can continue to suffer frost damage even after being rendered.

 

[diy_fun_uk]

thanks for advice. i'm 99% sure it's the same bricks that are used around bottom of the property and i'd wondered why none of those were suffering the same fate however must be as you say i.e. above dpc level. funny you mention rendering over them cause i'd thought about that as well.

 

[RonnyRaygun]

thanks for advice. i'm 99% sure it's the same bricks that are used around bottom of the property and i'd wondered why none of those were suffering the same fate however must be as you say i.e. above dpc level. funny you mention rendering over them cause i'd thought about that as well.

Even below dpc on a dwelling they won't be as exposed as in your steps, so are less likely to spall in that location.

 

[diy_fun_uk]

thanks for advice. i'm 99% sure it's the same bricks that are used around bottom of the property and i'd wondered why none of those were suffering the same fate however must be as you say i.e. above dpc level. funny you mention rendering over them cause i'd thought about that as well.

Even below dpc on a dwelling they won't be as exposed as in your steps, so are less likely to spall in that location.

thanks. if i replace and ensure gaps (e.g. at top of stairs) are blocked, will this stop the blowing happening as quickly, or will it make no difference?

 

[^woody^]

Rendering a wall susceptible to frost damage like this one, is the last thing you want to do. Render will fall off just like the fronts of the brick have done

 

[RonnyRaygun]

Rendering a wall susceptible to frost damage like this one, is the last thing you want to do. Render will fall off just like the fronts of the brick have done

Not if it's well secured as described. I've got examples of this where rendering has lasted 20 years with no spalling. If 20 years isn't long enough then maybe he needs to rebuild the wall. If he's willing to wait 20 years before rebuilding, get it well rendered as I described above.

It's not a perfect solution but the OP might prefer a quick fix that lasts 20 years than the hassle of rebuilding, which is the only practical alternative, other than replacing the bricks one by one as they spall.

 

[RonnyRaygun]

thanks. if i replace and ensure gaps (e.g. at top of stairs) are blocked, will this stop the blowing happening as quickly, or will it make no difference?

Might slow it down a bit but probably not much...

 

[diy_fun_uk]

thanks for continued replies all. i'm 1/2 tempted to have a go at rebuilding the whole structure but maybe too big a task as a first bricklaying/building project?

 

[^woody^]

I've got examples of this where rendering has lasted 20 years with no spalling.

Your examples are the same bricks in the same situation, experiencing the same damp and exposure as the OP's?

 

[RonnyRaygun]

I've got examples of this where rendering has lasted 20 years with no spalling.

Your examples are the same bricks in the same situation, experiencing the same damp and exposure as the OP's?

No, worse exposure conditions. More than one boundary wall (half brick thick) retaining about 18" of soil. Bricks spalling all over. Rendered as described in the early 90s and still perfectly sound.
Admittedly Fife might have more severe frosts than Gloucestershire, but other than that I'd say the conditions were more severe.

As I said Woody, it's not a perfect solution but it will look a lot better for a lot longer than spalling bricks. Replacing the bricks one by one is more trouble than it's worth and will look a mess, and he might not want the trouble of rebuilding.

Although reading the last post it seems he's willing to have a go. To the OP, if you want to have a bash at rebuilding, go for it, just make sure you use class F2 bricks.