Internal brick walls growing thick white furr, WHY???

[suggett1976]

I currently have converted a barn/garage into a usable room.

The internal walls were insulated and plaster boarded and sit on the origonal brick wall. (around 5 cources high)

Since it has been finished the brick walls have been growing a white furr on the bottom two cource (below damp cource i think). This never happened when it was a cold garage.

The brickwork was sprayed with a week diluted conctete hardener to keep the brickwork dust free.

All the brickwork was sprayed and the furr is only growing on two of the walls not all of them.

Anyone know why or how to stop it?

please see picture at



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• suggett1976
• 4 Jan 2010
• 1

 

[Nige F]

have a search around for eflourescence

 

[Chukka63]

looks like rising damp to me

 

[noseall]

You are showing about two courses of bricks that are below dpc in an internal situation.
This is fundamentally wrong. Either the dpc needs dropping or the floor level needs to be raised 150mm.

 

[suggett1976]

Remember that when the walls were constructed it was for a garage not a habbitable room.

The bricks dont feel or look damp, its not all the way round just in two corners and its a dry, light, white, fur.

 

[dave1953]

Definately Hygroscopic salt contamination from free water rising to DPC level. Noseall is spot on with recommendations. What are the exterior ground levels like in relation to problem walls? If their anywhere near DPC level they need reducing to below floor height.If rising damp is the problem then the cheapest way out of this problem would be to inject a new chemical DPC at required height.The good news is rising damp will not breach the physical barrier of your existing DPC but as your photo's show the damp [ through capillary action ] has travelled up the brickwork through the mortar beds and perps.

 

[suggett1976]

im starting to agree with you.

After looking into eflourescence looks like your all right.

No what to do.

Do you think treating it with some sort of product will sort it or chemical inject a new dpc.

 

[dave1953]

Hygroscopic salt contamination develops into efflourescence whereby any moisture internally is absorbed by the salts and will always show spoilings such as you have.Eventually they will become deliquescent [ saturated] and then you will have a bigger problem,As posted before have a good look at external ground levels or any other possibility of external water ingress.if everything is fine then a chemical DPC injection with a high silicon content will sort it but be aware it takes a long time to dry fully after injection.

 

[Chukka63]

even if the ground level is lower than the DPC its not going to stop the damp rising.

 

[dave1953]

The new DPC will have to be injected below internal floor level to be succesful and prevent the rising damp and it's consequences.Tanking is another method , ie up to existing DPC level but with the exposed internal brickwork it's not really an option.

 

[noseall]

Remember that when the walls were constructed it was for a garage not a habbitable room.

Ok, let me ask you this then. Do the house floor levels differ from the garage, i.e. do you step down into the converted garage?

 

[Deluks]

http://www.youtube.com/watch?v=G2eUopy9sd8

 

[suggett1976]

Remember that when the walls were constructed it was for a garage not a habbitable room.

Ok, let me ask you this then. Do the house floor levels differ from the garage, i.e. do you step down into the converted garage?

No its a stand alone barn. Its not attached to anything.



[GALLERY=media, 18341][/GALLERY]

If you look at the picture the fur is on the wall that is under the front window and the left hand side wall, (either side of the door.

There is no step in or out, just the door fresh hold.

 

[suggett1976]

I have just remembered that there is no guttering, perhaps having some fitted would help.

I cant remember what the concrete is like outside, i.e whether water collects or not.

 

[noseall]

Then in my opinion it is a design fault.

The floor levels throughout the building needed to be raised by 150mm.

A previous poster suggested injecting a dpc, i have no faith in this whatsoever.