40mm Gap between blockwork

[Bri44]

Hi all.

I`m having render repairs done and have noticed that the mortar between an exposed block is 40mm wide. If it`s like this up the whole elevation what are the possible issues?

The other side of the house are 10mm but there are cracks in the blockwork. One vertical crack is 18 foot long and getting longer. Waiting on the developer sending a structural engineer.

 

Any advice appreciated.

 

[bassanclan]

I don't think the 40mm joint will be a problem.

If a structural engineer is coming he will be able to provide an opinion, but you may want an independent opinion.

Is it a new build house with nhcb warranty?

 

[Bri44]

The house is 7 years old. It was a show house. I bought it from the developer Feb 2017.

It has an LABC warranty.

Would the mortar not cause structural issues regarding the strength etc?

 

It is recommended that mortar joints should be no more than 10mm.

 

I`ll see what their engineer says and look at getting my own.

[Declan52]

It will be fine. I have seen kerbs, lath and all sorts of things built into walls of houses and they are still standing.

[Mr Punter]

No issue as long as it is not throughout but it is unusual if the crack is through the blocks as well as the render.

 

It is good to get render cracks sorted as water can get in behind it and freeze / thaw can take off large sections.

 

It is very difficult to get the patches so they will not show, so unless they are serious I would just fill and paint.

 

Any cracks in any brickwork?  Are you on clay or made ground?  If no to both I would not worry.

[Bri44]

If you look at pictures in the first post you can see the cracks go right through the blockwork and mortar and through the render which is why it was cut out. 

This is a different wall to the one with the 40mm mortar. 

Why would they make the gaps that wide? 

 

I`m on clay ground. 

Edited August 3, 2020 by Bri44

[Declan52]

It's just the way it works out when you bond a wall out. They really should have space out a few blocks so spread the extra 30 mm over 4-5 blocks but it won't make no difference.

The crack could be just from the house drying out.

Is it on the inside as well or does it continue on down the wall???

[Bri44]

I can`t see if it is on the inside due to plasterboard and wall paper. 

The biggest crack that has been cut out is 18 foot long and extends a further 15 down as a hair line crack in render so the blockwork is most likely cracked behind it.

There are numerous other cracks mainly at window corners. They have cracked blockwork too.

 

This cant be from drying out as its 7 years old.

[Gus Potter]

Cracking crops up on a petty regular basis and it can cause concern to say the least when it's your home. It is a pretty complex subject but here is an attempt at a lightheated over view of some of the in's and outs. I have caveated some stuff here and there.

 

Looking at the photo (in insolation) that Bri44 posted the crack is relatively small in nature. If you can stick your finger in a crack then you should take action and seek advice. If you notice the crack is getting slowly wider or translating (moving sideways say) over perhaps a few months then think about getting some advice but don't leave it, if days or less then act quickly and take professional advice.

 

You need to be a bit like Columbo here. Strangely, small cracks are often harder to diagnose than big ones. There may be only one or two cracks or there may be lots of small hairline cracks. Often when you have say one big crack the causes are more easily indentified.

 

The stating point is to recognise that houses move all the time. The materials they are constructed from tend to be different - timber -  steel - concrete - brick etc and all these materials age and behave in different ways. They expand and contract differently when the temperature goes up or down for example. The house sits on the ground and this too moves about.

 

Bri44 has a clay soil. Clay behaves in a different way from say sandy / gravel type soils. One key difference is that they can shrink and swell depending on how much water they have in them (moisture content). With that in mind some of the things you look at are:

 

Is the site level? Are the founds at the same or different depths - If you have a dry summer then the upper layers of clay tend to be drier than the ones below so they shink by different amounts. Thus the foundations go up and down by different amounts and this leads to differential movement.. which can cause cracking.

 

Do you have any trees or hedges near the house. When in leaf the vegitation sucks the water out the clay soil and causes it to shrink. If you have cut down a tree then it can take a number of years for the soil to read adjust and it will move a bit (usually swell) when it does so.

 

If you have a leaking drain then it can cause the clay to swell locally and this can lift the foundation up while the rest is staying still or shrinking or moving down under perhaps dry summer conditions. Again, if you have installed a new drain that is deep with say pea gravel round it you can sometimes drain the clay and this can cause it to shrink.

 

There are a multitude of factors to consider so it's not always easy. If you have a house with very deep foundations at one end and shallow ones at the other and with a lot of infilled ground round the house at the deep end then as the fill settles over time it can drag down the walls a bit, add load to the founds via the dragging on the walls and they settle a bit more. Often if you are designing piles with made ground you'll examine this effect closely.

 

Moving up to the superstructure. The type and shape of the cracks can tell you a bit. You have a look at where any movement joints are placed in the walls and if they are in the right location.

 

Has the building been altered? If you have knocked out a load bearing wall and put in a beam you often change the way the founds are loaded and this too can result in a bit of cracking.

 

Importantly you want to look at the rest of the house. Are the roof tiles out of alignment. Go inside the attic and look here. Small movements at ground level can be amplified up at roof level so are sometimes easier to spot. Are the doors and windows working ok.. have you notice they are starting to jamb in places? Has the house been left unheated or over heated... are the floors level. Is there other development going on, under or near your house..

 

The above is just a flavour of what you want to look at. Once you gather all this information you hope that you'll have some idea as to the causes. Then you work out if you need to do anything or just monitor the situation and see if things settle down. More often than not for small cracks it a case of keep an eye on it. You can use "tell tales" or precise levelling techniques to montor movement before you resort to drastic measures.

 

For the curious there is a good document published by the BRE (BRE251) which gives some good guidance and goes some way towards categorising the size and type of cracks.

 

Lastly, Columbo always solves even the most complex of cases. But with small cracks you may just end up with a short list of suspects but no arrest and subsequent conviction.

 

 

 

 

 

 

 

 

 

 

 

[Bri44]

Thanks for the reply Gus.

Every now and again two internal doors swing open or swing closed if that makes sense. The side gate attached to the house right under the 18 foot crack drops down so hinge side nearest house is higher than the opposite side with bolt. I have to adjust bolt so that it fits.

 

Here are some pictures of the house. First one is where i have marked cracks. You can see the 18 ft crack with 4ft crack underneath. The 4ft crack now meets the 18ft crack.

 

 

[Bri44]

In this picture you can see that the cracks have been cut out horizontally from the 18ft crack.  The top horizontal crack is above the one you can see, level with the next level of  scaffold boards. I have marked in blue the horizonal cracks.

[Bri44]

Here shows the horizontal cracks marked in red. Take no notice of wonky red line, it should be straight. The red line shows the path of the 18 ft plus crack.

[Russell griffiths]

I think it’s time to consult the legal department at your insurance co and appoint an independent surveyor and structural engineer. 

I wouldn’t listen to a word the one from the developer says, who’s paying him. 

[MikeGrahamT21]

Blocks from original photos appear to be aircrete, they are prone to cracking like this, probably just looks worse as the render has taken some of the block with it when its been removed.

[Bri44]

1 hour ago, Russell griffiths said:

I think it’s time to consult the legal department at your insurance co and appoint an independent surveyor and structural engineer. 

I wouldn’t listen to a word the one from the developer says, who’s paying him. 

 

Yes I`m thinking of having my own structural survey. This is one of many issues. Had the roof replaced twice already. It` not the dream home i thought i was buying.

[Bri44]

16 minutes ago, MikeGrahamT21 said:

Blocks from original photos appear to be aircrete, they are prone to cracking like this, probably just looks worse as the render has taken some of the block with it when its been removed.

 

Why are they used if prone to cracking? There must be a reason they crack, ie movement, subsidence.

[MikeGrahamT21]

They get a lot of post install shrinkage, especially if they had been stored incorrectly on site before use (basically in the rain, they should be kept as dry as possible). The cracking is generally just cosmetic and nothing more.

 

They're used as they help developers achieve certain u values cheaply and quickly.

 

Obviously get it proper checked to confirm, but it may just be a case of crack stitching to ensure they don't show through again in the render, and some expanded metal lath attached to the blocks and then rendered in for additional strength at these points.

[Onoff]

13 minutes ago, Bri44 said:

 

Had the roof replaced twice already. 

 

In 7 years? 

 

What was wrong there and why twice?

[Bri44]

26 minutes ago, Onoff said:

 

In 7 years? 

 

What was wrong there and why twice?

 

It has a pitched roof with a flat gulley around. The gulley was lower than the exit point for the rain water so it pooled up like a moat. I was told the pitch roof was constructed wrong. First roofer took 3 months to replace roof. It was not done right. LABC said not correct. Next roofer ripped everything off first roofer did and took a further 6 months to complete. 

 

Whilst second repair was in progress it rained heavy on a Sunday afternoon. Water is pouring through my ceiling.  I`m there with buckets catching it to stop it going through the next floor. I ring emergency developer number, no one answers. finally get an answer after 40 minutes only to be told because it`s raining no one can be sent out due to health and safety reasons. Could not make this up. I have another thread on here about all my DPC ground levels wrong. Most has been rectified now after a 2 year battle with developer. Floor tiles are cracked at base of door frames. Skirting boards not meeting in corners, filled with bodge and painted over. Lots of other issues. 

 

 

Edited August 4, 2020 by Bri44

[Bri44]

28 minutes ago, MikeGrahamT21 said:

They get a lot of post install shrinkage, especially if they had been stored incorrectly on site before use (basically in the rain, they should be kept as dry as possible). The cracking is generally just cosmetic and nothing more.

 

They're used as they help developers achieve certain u values cheaply and quickly.

 

Obviously get it proper checked to confirm, but it may just be a case of crack stitching to ensure they don't show through again in the render, and some expanded metal lath attached to the blocks and then rendered in for additional strength at these points.

 

 

I asked a builder who lives round the corner to have a look. He said there is no expansion mesh i think between the layers of the blocks and no mesh under stress points like windows.

[MikeGrahamT21]

11 minutes ago, Bri44 said:

 

 

I asked a builder who lives round the corner to have a look. He said there is no expansion mesh i think between the layers of the blocks and no mesh under stress points like windows.

 

Yeah, its known as bed joint reinforcement, and will stop the cracking, its not essential for structural reasons though, just cosmetic. The post build fix is helical bars ground into the blocks to stitch them together.

 

I bet you are absolutely gutted about this house?! Unbelievable the quality of new build.

[Bri44]

Yes I`ve had issues from day one. I have had to fight them every step of the way to get them to fix faults. 

Three quarters of the development have wrong DPC levels, air bricks covered etc. 

 

My concern is these repairs will show even after painted, will devalue the house and make it hard to sell.

 

Here is another image of the crack in another part.

 

 

[Russell griffiths]

I think it’s time to face facts, appoint a solicitor, final outcome they need to buy it back at market value. 

Its a lemon. 

Or get it patched and sell it on if you can live with yourself. 

I personally would get the developer to buy it back. 

[Mr Punter]

47 minutes ago, Russell griffiths said:

I think it’s time to face facts, appoint a solicitor, final outcome they need to buy it back at market value. 

Its a lemon. 

Or get it patched and sell it on if you can live with yourself. 

I personally would get the developer to buy it back. 

 

Unless they are a large prestige housebuilder I would say there is very little chance of that happening.

 

Sadly the way the industry works is that trades are on a price and most do not care about quality work.  Site managers come and go and are not full time employees.  Results can be shoddy.  The parapet, curved wall and clay soil have not helped here.  Many of the housebashers stick to foolproof designs that can be built using little skill and at a known cost.

[Bri44]

1 hour ago, Russell griffiths said:

I think it’s time to face facts, appoint a solicitor, final outcome they need to buy it back at market value. 

Its a lemon. 

Or get it patched and sell it on if you can live with yourself. 

I personally would get the developer to buy it back. 

 

How successful are people in making them buy a faulty house back?  There`s no denying i`ve had all these issues and probably a 1000 emails between us.