Author Topic: Single Skin Garage Wall - Damp  (Read 19781 times)

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TaylorWimpeyDidThis

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Single Skin Garage Wall - Damp
« on: January 11, 2014, 07:11:13 pm »
I'm curious to know what others think is an acceptable amount of damp to track across a brand new single skin garage wall.

The two block pillars and upper bricks of our 4 month old garage showed signs of damp during the first spell of rain before Christmas https://db.tt/MJTH1cec - I initially put this down to 3 holes in the eaves, which go all the way through. 1. https://db.tt/HfrVZX51 2. https://db.tt/shUf2fDC and 3. https://db.tt/AnpQ396k One of these was so big I've jammed it up with plastic bags.

The general pointing / brickwork on the external wall is shoddy with lots of small cracks and gaps. The wall has been exposed to the wind and rain and, as with the main house, you can see the saturation of the bricks compared with the lighter bricks that have been sheltered from the weather.

With the following two lots of rain between Christmas and New Year the entire wall inside the garage was saturated and wet to touch. Items placed on shelves next to the wall have soaked up a lot of moisture.

I've been running a dehumidifier for 10 days and removing approx 4 litres per 12 hours. Obviously some of this will be the normal outside air as the garage is not sealed as well as a house. What I can't understand is that although the upper walls seem to be drying out, the floors and lower walls are still soaking wet, this is below the damp proof layer and well above the ground level of the garden.

1.https://db.tt/KdroTTTo   2.https://db.tt/EiPrhv4f   3.https://db.tt/T31Gw6S7

4.https://db.tt/X2ECEUp2 5.https://db.tt/z4QFJ5ls    6.https://db.tt/9ddZ4Jag

Several other garages are experiencing the same issue and Taylor Wimpey is simply saying they don't build weatherproof garages and that they are not designed to be waterproof as they are designed only to keep cars in.


The Brickkicker

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Re: Single Skin Garage Wall - Damp
« Reply #1 on: January 12, 2014, 10:48:24 am »
From your photos only , and as a result of some experience in this particular issue

I don't believe that the water is a result of the small holes under soffit in brickwork, although they should be done, I do believe it's penetration through the brickwork

so ..First have a look at the document I sent you - this is the NHBC's written position on the issue.

It confirms what your site manager said - and  that the NHBC say a single skin wall is acceptable , and that they recognise it will allow water penetration in an exposed area.

I don't think your location could really be classed as exposed - unlike somewhere on the coast or on the top of a hill

That said - my personal opinion does not agree with the NHBC and I have challenged this before A NUMBER OF TIMES , but to no avail - they say if the client wishes a water resistant garage they should coat the outer walls with some form of water repellent finish.

Sorry to be the bearer of bad news on this. I might suggest you push for them to finish the external walls affected with a barrier!
There are many out there. although I don't endorse any of them to be 100% effective
Also show me a single garage you can fit a car in and get out of ....!!!!!
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Re: Single Skin Garage Wall - Damp
« Reply #2 on: January 13, 2014, 09:14:08 am »
Here is the NHBC's standard regarding single skin garages.... Chapter 9.1 D5:
"d) adequate resistance to rain and ground water
A damp-proof course should be provided at a level at least 150mm above the level of adjacent ground. This dpc will protect the wall from rising ground moisture.
Garage walls constructed from a single leaf of masonry, such as brickwork or blockwork approximately 100mm thick, will not be impervious to wind driven rain and consequently could become damp.
In areas of severe exposure, single leaf walls may require a high standard of workmanship and possibly surface treatment to prevent an unacceptable level of rain penetration.
Where a garage is integral or attached, the design should ensure that dampness cannot enter the dwelling.
Where a floor is below ground level, precautions should be taken to prevent the entry of ground water by:
tanking
use of dpcs and dpms
drainage of ground behind the wall."


There have been a lot of new home buyers complaining about damp walls to single-skin garages over the last few weeks, not surprising given the wind driven rain. Including the post here "Flooded Garage" on 10 January 2014.

A Dehumidifier will help dry the brickwork out or alternatively you could leave the garage door open and let the air do it. As the moisture/damp will dry out from the top down as gravity will pull the water down to the bottom.  Any walls below DPC level will not dry out until the ground is dry.  They will be affected by damp rising from the wet ground by capillary attraction.  The DPC is doing its job although a second lower DPC may have also been a good idea...........but then again this is Taylor Wimpey!

The Standards do give reference to "surface treatment" ...sealing with Thomsons Water Seal (or similar) and this oes help and control the problem of damp in single skin garages. It is one area where the NHBC standards are quite clear and in my view reasonable. Garages are not habitable rooms. If watertightness is required, there are options available for new home owners.

And as for single garages being too small have a look at this.......
"Single Garage too small for a car"
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crh

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Re: Single Skin Garage Wall - Damp
« Reply #3 on: January 13, 2014, 12:22:08 pm »
What is the NHBC's position if there are electrics in the garage?
Surely the electrics would need to be IP if the garage isn't weather proof

New Home Expert

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Re: Single Skin Garage Wall - Damp
« Reply #4 on: January 14, 2014, 09:11:26 am »
Electrics in all garages are required to be protected using an RCD.
These trip out on the slightest current leakage so even in damp conditions, a homeowner would be safe.


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TaylorWimpeyDidThis

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Re: Single Skin Garage Wall - Damp
« Reply #5 on: January 18, 2014, 11:55:22 am »
Thanks NHE & Brickkicker

I'm hearing that more houses on the development are suffering the same issues.

It's galling that we've never experienced this in 20 years of home ownership across 6 properties, all with single skin garages (some in more exposed locations / positions that our current property) - I agree that we have had exceptional weather - but the problems were evident after the first 2 days of heavy rain and wind before Christmas.

I can only assume that the combination of cheap bricks and mortar are to blame. I'm also concerned what will happen when we get a period of freezing temperatures as this will crack the mortar, making for a more porous wall.

Taylor Wimpey's stating that they only advise cars being stored in the garage is an interesting one - The Southern Counties Director David Brown, made a joke when he visited our property saying "you're not going to be storing a car in there, are you?" with a big smile on his face!

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Re: Single Skin Garage Wall - Damp
« Reply #6 on: January 20, 2014, 07:56:51 am »
Firstly, I am surprised that David Brown has still got a job after all the problems you and other new home buyers have had with Taylor Wimpey on this site and his apparent indifference!  I think his latest comment was an indication that he believes that the garages are TOO SMALL to put a car in - similar to the Persimmon new home owner featured here!  Amazing that he thinks this is amusing!  

It is true that the bricks may be more absorbant than others available.  
I am not sure price would make this more or less likely though!  The mortar too could be a weaker mix.  
But my guess is that the joints were not fully-filled, both horizontal and vertical.  
Unfortunately the only way to check this would be to take out some bricks.  You could video the bricklayers working though.  Check to see if they are laying frog up for a start and have fully mortared the ends of the bricks, not just 'top and tailing'.

Another cause may be that the bricks were already saturated during the build and could not cope with the extra driving rain. I expect your next issue will be efflorescence of the brickwork. This is caused by salts being drawn out of the brick as it dries out after becoming wet, either during the build (which is most common and likely) or after wet weather. As the water evaporates, it leaves the salt behind, which forms a white, fluffy deposit, that can normally be brushed off. The resulting white deposits are referred to as "efflorescence" in this instance.

Since primary efflorescence brings out salts that are not ordinarily part of the cement stone, it is not a structural, but, rather, an aesthetic concern.  Efflorescence can often be removed using phosphoric acid. After application the acid dilution is neutralised with mild diluted detergent, and then well rinsed with water. However, if the source of the water penetration is not addressed (rising damp, leaking rainwater pipes or gutters for example) efflorescence may reappear.


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