Condensation or penetrating damp?

[JerryM]

Have added my 2p



I think penetrating for the mould caused by the double glazing installation

I exclude condensation (on the basis that its only in the bay and was never there before). Ventilation is key to eliminating condensation and could be down to the window change but I feel the cracks are overriding.

Only other thing is the mortar is quite powdery on the upper bay

i've had experience of this type of brick before - it badly needed repointing and the rough surface of the brick makes for a long job. I don’t know whether it’s the type of brick but for some reason the lime mortar is very soft (house build 1930’s).

this won’t be the primary cause though although it won’t be helping. The bay will be single skin – so when the mortar gets wet it will soon travel to the inside.

since the double glazing was fitted we have had mild cracking, which I was told was just settling. Could this be related?

Bays are a real nightmare in terms of their construction (shoddy comes to mind but obviously they are not) – yours actually looks a good one – slated over the top well impressed.

The trouble is they are single skin and a right nightmare to support if the windows are changed. I am sure the cracking was just settling but it should not have happened. It could be due to the construction of the windows, the support during the changover or as shytalz says simply down to the packers (believe me they are crucial to a good job). What’s important is does the window look right – if not get them back – it’s clearly not a top notch job and not what u paid for.

These cracks will definitely let moisture in and be the cause of the mould. They need repointing. also check the sealant has no gaps all the way round the window - just a small gap - a few mm will let lots of water in when it rains.


My sentiment is with shytalz. The trouble is your up against it unless the firm is a national with a name to protect. If not I’m afraid if u can live with how the window looks ie levellness than my advice would be to dig out and repoint the cracks, put a mould killer on the wall followed by a stain block and wait and see. I think and hope that will sort it.

 

[Shytalkz]

...I don’t know whether it’s the type of brick but for some reason the lime mortar is very soft (house build 1930’s)...

It can be due to impurities in the lime itself before being done in the kiln to make quicklime; the quicklime being inadequately slaked; or if it's wetted up for laying or over-wetting of the bricks before laying, which causes some chemical reaction or other (I'm not very good at chemistry!) in a non-hydrated lime and is a big no-no; it can also be due to inadequate protection to the mortar whilst it cures; and things that shouldn't be in the sand, like salt.

 

[Shytalkz]

...The trouble is your up against it unless the firm is a national with a name to protect...

And the biggies are not immune to denials after shítty installs either: one such company keeps me gainfully employed as their expert witness for court action at ££smany/hr sorting things just like this, invariably after they've been arguing with the client over several years and causing major resentment.

I even suggested that they paid me a sizeable annual retainer and I would go and check their bigger jobs before they signed them off, ending up charging them less than I do for the ones I get involved in when there's a dispute and them retaining their customer goodwill into the bargain, as well them as having someone to sue if I got it wrong. But they'd rather play the percentages game - and lose every time. I've never yet acted on instruction from them where I didn't agree with the householder that the work was defective. Heyho, horses to water and all that...

 

[JerryM]

Skytalkz,

thanks for clearing up the lime mortar - it's been bugging me for a while.

your credentials are now almost off scale with a doctorate in chemistry whilst practising law and self building as a hobby.

 

[kevin_robson]

Thanks again guys. Really appreciate your help. I've arranged for them to come out and have a look. They are not a national, but are very well known and 'reputable' locally.

That said we had a nightmare with them fitting it. Took about 4 months to get the door fitted correctly. I did ask about the cracks initially but was told not to worry and it was just settling. Unfortunately I didn't know what was acceptable and what wasn't.

If they dont play ball and I need an independent local opinion, who should I look to - will any builder be able to advise?

Irrespective of blame I'll get the repointing done, at least on the actual cracks. I have a plasterer friend who pointed out the pointing really needs doing. He offered to do it but I was a little worried about the pourous nature of the bricks - he's a tad on the slapdash side sometimes - is it easy enough to point this type of brick without making a mess and getting mortar in the holes in the bricks?

In short, can any mug do it or should it be done by professional who is used to doing this in order to look good.

 

[Shytalkz]

Skytalkz,

thanks for clearing up the lime mortar - it's been bugging me for a while.

your credentials are now almost off scale with a doctorate in chemistry whilst practising law and self building as a hobby.

Structural engineers do it with minimum stress, donchano

 

[Shytalkz]

That said we had a nightmare with them fitting it. Took about 4 months to get the door fitted correctly. I did ask about the cracks initially but was told not to worry and it was just settling. Unfortunately I didn't know what was acceptable and what wasn't.

Uhoh, alarm bells...still, they might redeem themselves. There is no excuse for any cracking: adequate shoring-up beforehand and packing after installation is all that is required. Oh and the installation of baypoles in circumstances such as yours...

If they dont play ball and I need an independent local opinion, who should I look to - will any builder be able to advise?

A shot across the bows with a solicitor's letter often has the desired laxative effect. If they don't respond to that, you will need either a chartered building surveyor (ouch, that hurt to say that!), or a structural engineer to look into it for you and prepare a report.

Irrespective of blame I'll get the repointing done, at least on the actual cracks.

Don't do anything at this stage: wait and see what they are prepared to do and take it from there. Take lots of photos.

In short, can any mug do it or should it be done by professional who is used to doing this in order to look good.

If he repoints in cement/sand mortar it will look cack - much like the repointing that was previously done. It's too impermeable, will trap moisture and fall off at some point, possibly taking the brick face with it. It's not complicated, but it needs a competent builder to do it and do it well. Noseall may travel...

 

[JerryM]

is it easy enough to point this type of brick without making a mess and getting mortar in the holes in the bricks

NO. i've pointed on this type of brick (it's got a rough surface) and it's the worst i've come across.

u need someone who's competent (ie does pointing for a living) and very careful otherwise it will look a real mess.

 

[noseall]

Packers should be like this:

Untitled

• Shytalkz
• 16 Apr 2008
• 1

[/img]

cheapskate! they're all broken.

 

[Shytalkz]

Lol, they were ones recovered from a window installation where there was no lintel and 2m-odd between window mullions. Guess what happened to the wall above....and guess how the window company acted for three years, before bowing to the inevitable...

 

[Shytalkz]

...bowing to the inevitable...

No pun intended

 

[kevin_robson]

Thanks again. But how do I find someone who does pointing for a living? I'm sure 99% of builders would tell me they can do it no problem.

And what sort of mortar do they need to use?

If they are doing this I have some other areas at the bottom of the house that are crumbling around the engineering brick damp proof course, despite them not cauing problems so far. What mortar would be needed for here too?

Thanks again for your continued help.

 

[JerryM]

any trained bricky will be able to do the pointing no trouble. all i'm saying is beware - your brick (from the photo's it looks the same as mine which has a rough surface) is not an easy brick to point without getting mortar all over the bricks.

ask all your friends and neighbours for a word of mouth recommendation as the 1st choice. if no good then get some quotes out of your local paper. the thing is u need to weed out the pros from the cons and that’s not easy until the work is complete. u need to ask them how they will do the job and fish for whether they think it's easy or not and how they will keep the bricks clean (get mortar on them and its a fair palaver to get it off - i found water to be the only way as both my soft & stiff brushes were no good but water ruins the pointing hence my caution). forget any that say it will be easy.

the reason i suggested someone who does pointing for a living (put "Pointing Specialist" into yell) is they will have done such work before.

i can brick lay but i ended up buying a pointing gun to do my brickwork. mortar is just standard. i go for 5:1 sand : cement with plasticiser to minimise the potential for cracking. u won't get an exact colour match to the existing but if the pointing is done well u won't really notice it.

i use the same mortar around damp proof course and i would probably add waterproofer as an extra precaution.

 

[kevin_robson]

Exellent. Thanks once again.
I'll leave you alone for a bit now until I've had the glazing firm back out

 

[Shytalkz]

...i go for 5:1 sand : cement with plasticiser to minimise the potential for cracking..

If the original is a cement/lime/sand mortar, then your spec may be ok, but not best practice if over a NHL or fat lime mortar, as it will be more impermeable, bringing with it the likelyhood of trapping moisture and blowing/erosion of face and repointing in time (look at pics of previous repointing attempt!)