Pointing outside wall...

BertieUK

Thank's tony6403 for your input. I will try a small section and carefully remove the old mortar to a depth of, as you suggest 12mm, it will be a time consuming job but will improve the overall appearance. Also considering the damp-course is two bricks above the surface of the drive.

Kind regards

BobUK

SailorSam

tony6403 wrote: »

For repointing, only about 12mm of existing mortar is removed.

12mm ??? That's no good for us oldies. I still think in feet and inches.

BertieUK

Taking out about 1" or so of mortar SailorSam, these metrics are sometimes confusing to me, well I am in my 70s so I know how you feel. Thank's again.

Regards

BobUK

Fed_Up_Tradesman

tony6403 wrote: »

For repointing, only about 12mm of existing mortar is removed. Relaying bricks on a new dpc is unnecessary if your dpc hasn't failed and the existing bricks are sound.
I think that should you decide to repoint, "bridging" will not be a problem.
I am not alone in this opinion. Quote from Jeff Howell (author)

the idea of dampness bypassing a DPC by “bridging” (by pointing or rendered plinths) is greatly overstated. Not least because cement-based mortars and renders are basically impermeable to moisture

Agree with your first point there Tony. My advice was for replacing a DPC which is what I thought the op was asking about. Hey ho.

Your second point is absolute nonsense imo.

Using your reasoning there seems little point in installing a damp proof membrane whatsoever - since you claim that cement-based mortars and renders are basically impermeable to moisture then maybe we should just stop using them altogether and rely on cement based mortars to stop damp rising up through our masonry. Maybe the building industry has been doing it wrong all of these past decades ...

Maybe you could explain why DPC's are never pointed up to cover the membrane itself - which is why they are always visible.

Myabe you could also explain why mortar snots between cavities should always be avoided too ...

And why waterproofing additives are added to rendering mixes too ...

Oh and to the op, as I said, be very careful how you remove mortar surrounding an old, brittle DPC. You will need lots and lots of luck imo.

tony6403

FuT we are talking here about removing 12mm ( Bertie please note - half an inch ) of existing mortar on the outside of the brickwork.
When it rains the brick faces , bed joints and perps above the dpc get soaked but dry out quite quickly with wind/sun.
If the dpc were to be bridged (perhaps the OP can do the job without this happening) any rising damp would be confined at most to the outer 12mm and would similarly dry out.
Bridging cavities is an entirely different situation. They are not normally vented and cannot dry out in the same way as the outside brick faces.
I am not suggesting that a dpc could be left out - we are dealing with repointing not new build.
The reference to "impermeable to moisture" etc. was , as stated ,from Jeff Howell who writes books about this sort of stuff.
Given that OP's property clearly needs repointing at the dpc , your method would be??

Fed_Up_Tradesman

tony6403 wrote: »

FuT we are talking here about removing 12mm ( Bertie please note - half an inch ) of existing mortar on the outside of the brickwork.
When it rains the brick faces , bed joints and perps above the dpc get soaked but dry out quite quickly with wind/sun.
If the dpc were to be bridged (perhaps the OP can do the job without this happening) any rising damp would be confined at most to the outer 12mm and would similarly dry out.
Bridging cavities is an entirely different situation. They are not normally vented and cannot dry out in the same way as the outside brick faces.
I am not suggesting that a dpc could be left out - we are dealing with repointing not new build.
The reference to "impermeable to moisture" etc. was , as stated ,from Jeff Howell who writes books about this sort of stuff.
Given that OP's property clearly needs repointing at the dpc , your method would be??

My method would be to use a diamond wheel very carefully trying not to touch & damage the membrane & facework, then repoint without bridging it with mortar, which is not impermeable to moisture, hence the need for a membrane.

But I don't take this type of work on.

BertieUK

I totally agree that the damp-course clearly needs to be repointed, that is my main concern as to what the best course would be.

I do not take jobs like these too lightly, it is so easy to make a completely botch job if consideration was not given to many, in my eyes, major elements that are present.

Today I took a very close up view of the damp-course and I find that it is extremely brittle, as one would expect of a 50+ year old property, on outside edges of the membrane.

I feel that this job is out of my 'comfort zones' but looking at my neighbours pointing of his damp-course, you cannot see it at al,l on much of the length, which scares me as to the person that did it was not clearly a tradesman.

It is not very often that I have to accept defeat but the experience of a qualified tradesman that woul do a 'proper-job' looks possible.

Sorry for going on about what, to some people, maybe a simple job, but how would I match the colour of the old mortar, because the mortar that I tried on one small, out of the way area, was very much darker in colour. Maybe getting some lime?

Kind regards to you all

BobUK

tony6403

Bob , I very much doubt that lime was used in the construction of your property. This practice generally stopped shortly after 1900. It is still used though in certain cases.
What mix ( parts sand to cement ) did you try. I imagine that you used red sand? A trial with yellow sand?
Also your trial area will probably lighten after a week or two.
Interesting reading here ( paragraph 4.09 )
www.hgs.org.uk/planningguides/pointing.html

BertieUK

tony6403 Many thank's for your input. The mix that I was advised to use was Multipurpose Mortar by Tarmac. Made by the experts for the professionals. ready to use just add water type. What I did not notice, at time of purchase, were the words 'Grey colour when dry'

Yes the reading was very interesting..

4.09 The major variable is the sand. A silver sand has very little colour. A soft builder's sand may impart a considerable amount of yellow, orange or brown colour. This is the sort of sand which discolours your hand when you pick up a wet handful. So the colour can be varied quite a lot by changing the sand. ..........

This looks like I would have to get a colour matching mix to suit, more than, through ignorance, what I was advised to purchase.

I think your suggestion of 'yellow sand' mix would work better.

I am starting to get concerned about what could be involved here from what has already been said and advised about the 'damp-course' condition.

Just as a matter of interest, what would be an average price 'per metre' to 'repair' the damp course only?

Kind regards

BobUK

BertieUK

Fed_Up_Tradesman wrote: »

Agree with your first point there Tony. My advice was for replacing a DPC which is what I thought the op was asking about. Hey ho.

Fed-Up-Tradesman.. With the greatest respect to you, my question, as follows was...

Quote The wall in question is a west facing which gets the full force of the weather. Considering that the damp-course also requires maintenence how best would you say I go about this? UnQuote.

This is a problem that must be present in thousands of properties and to remove the bricks and relay the damp-course I thought was a very extreme measure to have to go through considering that the DP is 6" above the drive.

If what you say is what the Building Regs require then there is no easier way of doing this.

I thank you for your time and patience,

Regards

BobUK