Wet Brick Patches on Exterior Walls - New Bulld

[Marlz05]

Hi all,

I am building a new house using Kassandra Multi Reds and using 125mm Drytherm insulation. I have noticed sections on the exterior brickwork soak up rain and remain damp after other sections have dried. These sections are mainly where the brickwork went up first. The cavity is full filled with the insulation throughout.  The roof is already in place and there are no leaks/issues.

Has anyone else had this problem and is there a remedy?

Thanks in advance.

[joe90]

I had a similar issue with my brick west facing wall, it turned out to be a fine crack in the mortar with a brick fill, small gaps tend to soak water through osmosis, crack widened and filled = no problem.

[MikeGrahamT21]

From what my dad has told me in the past, retired builder, there is an up and a down for a brick, an experienced bricklayer will know the difference, he told me if you get it the wrong way it will hold the water and be more susceptible to blowing in frosty weather, the right way encourages the water to run off.

 

whether that still reigns true today I’m not sure but could explain

Edited July 15, 2023 by MikeGrahamT21

[Discoeye]

23 minutes ago, MikeGrahamT21 said:

From what my dad has told me in the past, retired builder, there is an up and a down for a brick, an experienced bricklayer will know the difference, he told me if you get it the wrong way it will hold the water and be more susceptible to blowing in frosty weather, the right way encourages the water to run off.

 

whether that still reigns true today I’m not sure but could explain

+1 for that being a possible reason, my dad was a bricky his entire life and often spoke of this .

[saveasteading]

1 hour ago, MikeGrahamT21 said:

there is an up and a down for a brick

Not always. 

Those with a hollow (frog) in one face have a right way up. The frog should be upwards and completely filled with mortar.

If not, it is weaker and perhaps the voids have some effect on permeability.

Some bricklayers have been known to do this wrong, for speed and to reduce mortar.

 

Some bricks have smiley shapes on them, and they are usually laid that way up for appearance.

I guess the shape affects how rain runs off.

 

Other than these, I am not aware that there is a right way up.

 

Perhaps the bricks haven't been mixed, so there are areas from the same batches, with different appearance and properties.

[MikeGrahamT21]

On 15/07/2023 at 22:57, saveasteading said:

Not always. 

Those with a hollow (frog) in one face have a right way up. The frog should be upwards and completely filled with mortar.

If not, it is weaker and perhaps the voids have some effect on permeability.

Some bricklayers have been known to do this wrong, for speed and to reduce mortar.

 

Some bricks have smiley shapes on them, and they are usually laid that way up for appearance.

I guess the shape affects how rain runs off.

 

Other than these, I am not aware that there is a right way up.

 

Perhaps the bricks haven't been mixed, so there are areas from the same batches, with different appearance and properties.

 

In my opinion thats incorrect on the frogged bricks, the frog should always go down ot discourage moisture from collecting, regardless whether its filled or not it will collect moisture, which will lead to face failure. The British standards say that the frog should be pointing up and have a full mortar infill, i suspect this is because they are focussed on strength over anything else, the majority of master builders would likely disagree and lay frog down.

 

The idea with the frog is to make a perimeter seal which would partially fill the frog with mortar, and also trap some air. Frogged bricks make it simple to know which way is up and down, as the frog is always pointing down. This way you have efficient use of mortar, no chance of moisture collecting, and also some stationary air which would be slightly insulating.

[ToughButterCup]

23 minutes ago, MikeGrahamT21 said:

 

In my opinion thats incorrect on the frogged bricks, the frog should always go down ot discourage moisture from collecting, regardless whether its filled or not it will collect moisture, which will lead to face failure. The British standards say that the frog should be pointing up and have a full mortar infill, i suspect this is because they are focussed on strength over anything else, the majority of master builders would likely disagree and lay frog down.

 

The idea with the frog is to make a perimeter seal which would partially fill the frog with mortar, and also trap some air. Frogged bricks make it simple to know which way is up and down, as the frog is always pointing down. This way you have efficient use of mortar, no chance of moisture collecting, and also some stationary air which would be slightly insulating.

 

Ya larn summat evry day yur ....

Thanks @MikeGrahamT21 - really interesting. I've often wondered what that dent was (is).

Now I'll know a frog when I see one.  I can see a really good row developing in the pub now...  couple of brickies get in our local

[Brickie]

Frog up for me. People lay frog down to save on mortar or sometimes to grind the joints down bit by bit if the work below was built over gauge. I’ve known of frog down work to be taken down if NHBC come across it. 

Edited July 17, 2023 by Brickie

[markc]

Agree with @saveasteading and @Brickie from BS (British Standards, not Bull Sh@t) frogs go up

[saveasteading]

2 hours ago, MikeGrahamT21 said:

focussed on strength over anything else

Bricks are there to hold the floors and roof up. Not a bad priority.

Also to keep the weather out.

2 hours ago, MikeGrahamT21 said:

majority of master builders would likely disagree and lay frog down.

 

Worrying. 

I don't think I've met a master builder to argue this with.

 

Frogs are only there to save clay. This reduces cost of course, hence all common gluttony have them.

The other justifications are just excuses.

'To show which way is down' is novel and rather self justifying  

 

But show me proof please and I will think again. 'Bricky says' won't suffice.

British Standards are not arbitrary.

 

Next time I see a frogged brick I will look at how much surface is lost using an unfilled  frog. About 2/3 lost bearing could be a big deal.

 

On any structural calculations there is a factor of safety for poor workmanship. Frog down uses this all up.  But we should all still do it right.

 

Go on brickies, mix up some more mortar, and fill the frogs.

Architects....specify bricks without frogs to be sure.

[MikeGrahamT21]

20 minutes ago, saveasteading said:

Bricks are there to hold the floors and roof up. Not a bad priority.

Also to keep the weather out.

Worrying. 

I don't think I've met a master builder to argue this with.

 

Frogs are only there to save clay. This reduces cost of course, hence all common gluttony have them.

The other justifications are just excuses.

'To show which way is down' is novel and rather self justifying  

 

But show me proof please and I will think again. 'Bricky says' won't suffice.

British Standards are not arbitrary.

 

Next time I see a frogged brick I will look at how much surface is lost using an unfilled  frog. About 2/3 lost bearing could be a big deal.

 

On any structural calculations there is a factor of safety for poor workmanship. Frog down uses this all up.  But we should all still do it right.

 

Go on brickies, mix up some more mortar, and fill the frogs.

Architects....specify bricks without frogs to be sure.

 

There is no proof in either direction, this debate has raged for decades...

 

Even at 2/3 bearing loss, a brick would still hold more than 10N, and being a non structural element would never hold that amount. All of the bricks on my bungalow are laid frog down from the 1960's and its still standing, because the brick holds no load aside from itself and its counterparts.

 

Also, the frog isn't there to just save clay (it does, but thats not the main point of having it), its to ensure that the brick gets baked right through without using excess energy or burning the outer parts

 

UP OR DOWN?

Some experts say that bricks containing frogs should be laid frog up so that the frog is completely filled with mortar. If the brick is laid frog down, the frog may not be completely filled with mortar. This would render the brick wall face-shell bedded, which gives less wall strength than full mortar bedding. 

Other experts say brick should be laid with frog down, for two reasons. First, a uniform bed of mortar can be laid more easily on the face that doesn’t contain the frog. Second, if the frog is laid up, any cavities left can hold water, which may cause frost damage and contribute to early brick deterioration. 

Some believe frog down is stronger, resulting in better cement adhesion and a stronger bond between bricks. 

Others believe frog up has better strength properties. The load is evenly spread throughout the width of the brick, all the way to its foundations. The debate has raged for generations.

Edited July 17, 2023 by MikeGrahamT21

[Mr Punter]

On 14/07/2023 at 19:39, Marlz05 said:

Has anyone else had this problem and is there a remedy?

 

I am doing a full filled cavity with brick outer leaf and I will coat the brickwork with Stormdry Masonry cream.  BBA approved, one coat application and 25 year protection life.

[saveasteading]

17 minutes ago, MikeGrahamT21 said:

There is no proof in either direction

The British Standard is based on research and qualifies as proof to me.

 

18 minutes ago, MikeGrahamT21 said:

Other experts say brick should be laid with frog down

I need to see proof, as you say.

 

18 minutes ago, MikeGrahamT21 said:

if the frog is laid up, any cavities left can hold water,  

errrm, that is reversed logic, surely.   If the frog is up and filled, then there are no voids. If the frog is down , pushed into mortar, then there are likely to be voids.

 

22 minutes ago, MikeGrahamT21 said:

The debate has raged for generations.

Between designers and supervisors instructing frog up, and brickies trying to avoid it. 

 

this is pretty conclusive too, ans surpisingly forthright.

 

https://www.wienerberger.co.uk/content/dam/wienerberger/united-kingdom/marketing/documents-magazines/technical/brick-technical-guidance-sheets/UK_MKT_DOC_Laying of Frogged Bricks.pdf

 

and another

https://www.marshalls.co.uk/commercial/bricks-walling/frogged-facing-bricks

 

QED I feel. I'm not trying to win an argument, I do think this is important, and I hope this is persuasive.

 

 

 

 

[saveasteading]

This has been interesting.  A few more findings.

• The only semi-official mention I have found of 'frog down' being maybe ok is from one brick manufacturer where they say frog MUST be up if the walls need it for structure, and MAY be down if not.
• Bent bricks should be laid in frowning shape, not smiling.
• I've found a London Common. The area of brick to brick close contact is shockingly low. As this is obviously on the perimeter, this could be a cause of faces spalling under load, where commonly rain or frost is blamed.
• There's interesting chat on some other forums. To summarise, most builders  commenting are saying  they have always done it that way, their first foreman told them so, and when you knock down an old wall it is always frog down. And they are not about to change. And everybody else is wrong, because they just are.
• Of course, a bricklayer is not called in if their wall spalls 30 or 50 years later, so there is no feedback. I'm used to having 15 years liability,  and 30 year old buildings are still around as references Also there is a big difference if brick walls are only a small part of  a  whole project, so insisting on frog up is not going to lose me the job on cost.

A closing thought. If I was a contractor, quoting for a brickwork package in competition, and was convinced that frog up is correct, then there would be a dilemma.

Allow the extra mortar and labour and time, and lose the job to those who don't?

Tell the client there are 2 options and 2 prices?  I could do it wrong and be cheaper?

Ask the client for instruction on frog up or down?

 

[Nick Thomas]

4 hours ago, saveasteading said:

I've found a London Common. The area of brick to brick close contact is shockingly low. As this is obviously on the perimeter, this could be a cause of faces spalling under load, where commonly rain or frost is blamed.

 

Heh, I did a small repair on my sister's brick-built porch made of "london brick" back in May, which I think are the same thing.

 

To add to the varieties you've researched here, the original work was done so that the frogs were facing each other - i.e. you got a diamond-shaped void filled with mortar every two courses. I assume it's like this all the way up the porch. I was not expecting that! The diamonds came out of the bricks very easily, so I decided to re-use them, copying the original method.

 

It was an absolute pig to get the "down" frogs filled when I was replicating it (I had/have no idea what is correct, of coursE).

 

Oh, and these bricks also had two different face textures - smooth vs. wavy imprints. I was focused enough on the frog situation that I didn't notice that and put them all in back-to-front 😬. My sister was kind enough not to insist that I re-do it.

 

It's a world away from your bigger projects, but I enjoyed reading your research and thought this real-world application might amuse you. Have some before/after pics!

 

You can see a bit of spalling on a few of them too 🤷‍♀️

 

Edited July 18, 2023 by Nick Thomas
note spall