Hi,

Following advice from this group, I am now staring to paint the inside
of my single skin brick garage with bitumen paint to waterproof it.
But... one wall is already covered in paint. I checked with the
manufacturer of the bitumen paint and they advised removing the
existing paint first. I had hoped I might be able to paint over it ;(

I don't know whether this is masonry paint or emulsion or what because
it was there when we moved in.

I have tried a flap disc in an angle grinder and it does remove most
of the paint but judging from the dust, it is also removing some of
the brick too. I know some people are quick to warn about the dangers
of angle grinders; are flap discs any safer? I presume the danger is
from discs shattering and high speed fragments flying towards the
operator?

I haven't used a wire brush for the same reason; I thought it would
scratch the bricks.

I tried a paint stripper, all I had at home was "yellow" nitromors. It
certainly took the top layer of paint off but the bricks are still
white rather than red, and I have now run out.

So what do you suggest I buy and try next?

A quick google suggested paint stripper but also sand blasting and
pressure washing. The problem would be that I have only emptied half
the garage and moved the rest into the middle, so to pressure wash I
would need to empty it completely. There was a suggestion that
pressure washing would damage the mortar though and this is not good
mortar to begin with. It is quite sandy and I have tried to repoint
where it has crumbled already.

I see you can get sand blaster attachments for pressure washers. Are
they any good? But aren't we back to where we began that any abrasive
will scratch the brick?

TIA

On 2 Sep, 14:18, Fred wrote:

big snip

I see you can get sand blaster attachments for pressure washers. Are
they any good? But aren't we back to where we began that any abrasive
will scratch the brick?

but if it's inside your garage AND you are going to slap bitumen paint
all over it - why does it matter if it's scratched/abraded? for the
bitumen paint plus whatever else, you *need* a good key (as,
presumably, the manufacturer you spoke to was intimating)?

Jim K

On 02/09/2010 14:18, Fred wrote:
Hi,

Following advice from this group, I am now staring to paint the inside
of my single skin brick garage with bitumen paint to waterproof it.
But... one wall is already covered in paint. I checked with the
manufacturer of the bitumen paint and they advised removing the
existing paint first. I had hoped I might be able to paint over it ;(

You probably can, but no manufacturer is going to tell you that. Suck it
and see on a small area

On Thu, 02 Sep 2010 15:14:02 +0100, stuart noble
wrote:

You probably can, but no manufacturer is going to tell you that. Suck it
and see on a small area

Hi. I have had since another email from a different manufacturer of
bitumen paint; this manufacturer has said you can over paint, so now I
don't know who to believe! I think your suggestion of trying a small
area is the only way to see.

In reply to Jim, since the wall will be covered I suppose it won't
matter about scratching the bricks with an abrasive.It's just it makes
a lot of mess and the garage is not empty. if it were empty, then that
would be a different matter.

Perhaps I'll try to skim the top layers of with a quick sand and over
paint what's left. What's best to us: a flap disc, a wire brush, I
wonder whether a sander would be adequate?

Thanks again.

On 2 Sep, 18:06, Fred wrote:
On Thu, 02 Sep 2010 15:14:02 +0100, stuart noble

wrote:
You probably can, but no manufacturer is going to tell you that. Suck it
and see on a small area

Hi. I have had since another email from a different manufacturer of
bitumen paint; this manufacturer has said you can over paint, so now I
don't know who to believe! I think your suggestion of trying a small
area is the only way to see.

In reply to Jim, since the wall will be covered I suppose it won't
matter about scratching the bricks with an abrasive.It's just it makes
a lot of mess and the garage is not empty. if it were empty, then that
would be a different matter.

dustsheets?

Perhaps I'll try to skim the top layers of with a quick sand and over
paint what's left. What's best to us: a flap disc, a wire brush, I
wonder whether a sander would be adequate?

for just this purpose I've used one of these in an angle grinder

http://www.toolstation.com/shop/p35654

(says in 230mm grinder? but I've used em fine in a 4" angle grinder)

- let it have a go all over
- any obviously loose stuff will fly off no bother with little
pressure from you
- if bits stay put leave em on and paint over
- steady away.....

Jim K

On Thu, 2 Sep 2010 12:17:59 -0700 (PDT), Jim K
wrote:

for just this purpose I've used one of these in an angle grinder

http://www.toolstation.com/shop/p35654

(says in 230mm grinder? but I've used em fine in a 4" angle grinder)


How strange. They sell this 75mm one for 4" grinders:
http://www.toolstation.com/shop/Powe.../sd1920/p68932

yet they sell the one you quoted, which is also 75mm, but state it
must be used in a big grinder. The wires in yours seem much more
substantial, do they think a small grinder would not have the power to
spin it? A big grinder will be heavy though.

Re. yours and Phil's question about why I was worried about grinding,
I did a google and found a number of postings on web sites and forums
advising against scratching bricks because it damaged the glaze. I
read these out of context: these were posts about removing paint from
external walls where the final appearance would have been important. I
suppose I was also unsure whether this was a purely cosmetic issue.
You are quite right that these walls will be covered and so I can
proceed this way.

I haven't got a wire cup (yet) but I do have a flap disc. I had
another go at it this evening and am making progress.

Thanks again.

"Fred" wrote in message
...
Hi,

Following advice from this group, I am now staring to paint the inside
of my single skin brick garage with bitumen paint to waterproof it.
But... one wall is already covered in paint. I checked with the
manufacturer of the bitumen paint and they advised removing the
existing paint first. I had hoped I might be able to paint over it ;(

I don't know whether this is masonry paint or emulsion or what because
it was there when we moved in.

I have tried a flap disc in an angle grinder and it does remove most
of the paint but judging from the dust, it is also removing some of
the brick too. I know some people are quick to warn about the dangers
of angle grinders; are flap discs any safer? I presume the danger is
from discs shattering and high speed fragments flying towards the
operator?

I haven't used a wire brush for the same reason; I thought it would
scratch the bricks.

I tried a paint stripper, all I had at home was "yellow" nitromors. It
certainly took the top layer of paint off but the bricks are still
white rather than red, and I have now run out.

So what do you suggest I buy and try next?

A quick google suggested paint stripper but also sand blasting and
pressure washing. The problem would be that I have only emptied half
the garage and moved the rest into the middle, so to pressure wash I
would need to empty it completely. There was a suggestion that
pressure washing would damage the mortar though and this is not good
mortar to begin with. It is quite sandy and I have tried to repoint
where it has crumbled already.

I see you can get sand blaster attachments for pressure washers. Are
they any good? But aren't we back to where we began that any abrasive
will scratch the brick?

TIA

Can't see why you can't over paint: it's only a garage after all.
On the other hand, as it is a garage, if you did want to get the paint off,
it is one place where you could slap on caustic soda or caustic soda based
strippers, and hose down. Getting paint off masonry is never easy - but
easier outdoors than in! (People who put gloss paint straight on to plaster
are swine!)

S

On 02/09/2010 19:10, Spamlet wrote:
wrote in message
...
Hi,

Following advice from this group, I am now staring to paint the inside
of my single skin brick garage with bitumen paint to waterproof it.
But... one wall is already covered in paint. I checked with the
manufacturer of the bitumen paint and they advised removing the
existing paint first. I had hoped I might be able to paint over it ;(

I don't know whether this is masonry paint or emulsion or what because
it was there when we moved in.

I have tried a flap disc in an angle grinder and it does remove most
of the paint but judging from the dust, it is also removing some of
the brick too. I know some people are quick to warn about the dangers
of angle grinders; are flap discs any safer? I presume the danger is
from discs shattering and high speed fragments flying towards the
operator?

I haven't used a wire brush for the same reason; I thought it would
scratch the bricks.

I tried a paint stripper, all I had at home was "yellow" nitromors. It
certainly took the top layer of paint off but the bricks are still
white rather than red, and I have now run out.

So what do you suggest I buy and try next?

A quick google suggested paint stripper but also sand blasting and
pressure washing. The problem would be that I have only emptied half
the garage and moved the rest into the middle, so to pressure wash I
would need to empty it completely. There was a suggestion that
pressure washing would damage the mortar though and this is not good
mortar to begin with. It is quite sandy and I have tried to repoint
where it has crumbled already.

I see you can get sand blaster attachments for pressure washers. Are
they any good? But aren't we back to where we began that any abrasive
will scratch the brick?

TIA

Can't see why you can't over paint: it's only a garage after all.
On the other hand, as it is a garage, if you did want to get the paint off,
it is one place where you could slap on caustic soda or caustic soda based
strippers, and hose down. Getting paint off masonry is never easy - but
easier outdoors than in! (People who put gloss paint straight on to plaster
are swine!)

S


If the paint is masonry, or anything water based, caustic won't touch
it, but might well soak into the brickwork and create a new headache.

If the surface is clean and reasonably sound, I'd be inclined to leave
well alone. Maybe a quick going over with a wire brush to remove loose
stuff, but abrasion probably isn't going to significantly improve the
chances of the bitumen bonding to it. The danger is always that it will
pull the old paint off, but that is usually obvious during the application

On Thu, 02 Sep 2010 20:08:44 +0100, stuart noble
wrote:

Maybe a quick going over with a wire brush to remove loose
stuff

I was going to remove all flaky patches anyway.

The danger is always that it will
pull the old paint off, but that is usually obvious during the application

I think this is what the one manufacturer was afraid of.

Thanks.

Fred wrote:


I see you can get sand blaster attachments for pressure washers. Are
they any good? But aren't we back to where we began that any abrasive
will scratch the brick?

They are spot cleaning tools. Doing an entire wall would take ages & fill
the garage with damp sand :-)


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On Thu, 2 Sep 2010 19:26:23 +0100, "The Medway Handyman"
wrote:

They are spot cleaning tools. Doing an entire wall would take ages & fill
the garage with damp sand :-)

I might have tried on the external side of the wall but not the
inside. I just wondered what they were like generally?

Fred wrote:
Hi,

Following advice from this group, I am now staring to paint the inside
of my single skin brick garage with bitumen paint to waterproof it.
But... one wall is already covered in paint. I checked with the
manufacturer of the bitumen paint and they advised removing the
existing paint first. I had hoped I might be able to paint over it ;(

I don't know whether this is masonry paint or emulsion or what because
it was there when we moved in.

I have tried a flap disc in an angle grinder and it does remove most
of the paint but judging from the dust, it is also removing some of
the brick too. I know some people are quick to warn about the dangers
of angle grinders; are flap discs any safer? I presume the danger is
from discs shattering and high speed fragments flying towards the
operator?

I haven't used a wire brush for the same reason; I thought it would
scratch the bricks.

I tried a paint stripper, all I had at home was "yellow" nitromors. It
certainly took the top layer of paint off but the bricks are still
white rather than red, and I have now run out.

So what do you suggest I buy and try next?

A quick google suggested paint stripper but also sand blasting and
pressure washing. The problem would be that I have only emptied half
the garage and moved the rest into the middle, so to pressure wash I
would need to empty it completely. There was a suggestion that
pressure washing would damage the mortar though and this is not good
mortar to begin with. It is quite sandy and I have tried to repoint
where it has crumbled already.

I see you can get sand blaster attachments for pressure washers. Are
they any good? But aren't we back to where we began that any abrasive
will scratch the brick?

TIA

I can't understand why you are concerned about scratching the bricks when
you intend to slop bitumen all over them.

--
Phil L
RSRL Tipster Of The Year 2008

On 2 Sep, 21:09, "Phil L" wrote:
Fred wrote:
Hi,

Following advice from this group, I am now staring to paint the inside
of my single skin brick garage with bitumen paint to waterproof it.
But... one wall is already covered in paint. I checked with the
manufacturer of the bitumen paint and they advised removing the
existing paint first. I had hoped I might be able to paint over it ;(

I don't know whether this is masonry paint or emulsion or what because
it was there when we moved in.

I have tried a flap disc in an angle grinder and it does remove most
of the paint but judging from the dust, it is also removing some of
the brick too. I know some people are quick to warn about the dangers
of angle grinders; are flap discs any safer? I presume the danger is
from discs shattering and high speed fragments flying towards the
operator?

I haven't used a wire brush for the same reason; I thought it would
scratch the bricks.

I tried a paint stripper, all I had at home was "yellow" nitromors. It
certainly took the top layer of paint off but the bricks are still
white rather than red, and I have now run out.

So what do you suggest I buy and try next?

A quick google suggested paint stripper but also sand blasting and
pressure washing. The problem would be that I have only emptied half
the garage and moved the rest into the middle, so to pressure wash I
would need to empty it completely. There was a suggestion that
pressure washing would damage the mortar though and this is not good
mortar to begin with. It is quite sandy and I have tried to repoint
where it has crumbled already.

I see you can get sand blaster attachments for pressure washers. Are
they any good? But aren't we back to where we began that any abrasive
will scratch the brick?

TIA

I can't understand why you are concerned about scratching the bricks when
you intend to slop bitumen all over them.

echo

On Sep 2, 2:18*pm, Fred wrote:
Hi,

Following advice from this group, I am now staring to paint the inside
of my single skin brick garage with bitumen paint to waterproof it.
But... one wall is already covered in paint. I checked with the
manufacturer of the bitumen paint and they advised removing the
existing paint first. I had hoped I might be able to paint over it ;(

I don't know whether this is masonry paint or emulsion or what because
it was there when we moved in.

I have tried a flap disc in an angle grinder and it does remove most
of the paint but judging from the dust, it is also removing some of
the brick too. I know some people are quick to warn about the dangers
of angle grinders; are flap discs any safer? I presume the danger is
from discs shattering and high speed fragments flying towards the
operator?

I haven't used a wire brush for the same reason; I thought it would
scratch the bricks.

I tried a paint stripper, all I had at home was "yellow" nitromors. It
certainly took the top layer of paint off but the bricks are still
white rather than red, and I have now run out.

So what do you suggest I buy and try next?

A quick google suggested paint stripper but also sand blasting and
pressure washing. The problem would be that I have only emptied half
the garage and moved the rest into the middle, so to pressure wash I
would need to empty it completely. There was a suggestion that
pressure washing would damage the mortar though and this is not good
mortar to begin with. It is quite sandy and I have tried to repoint
where it has crumbled already.

I see you can get sand blaster attachments for pressure washers. Are
they any good? But aren't we back to where we began that any abrasive
will scratch the brick?

TIA

The only downside of not stripping it first is that the underlying
paint might peel off one day. Since its not going to come off easily
I'd almost certainly overpaint.


NT