From the street I can see a few cases where a TV mast has been strapped
to a chimney (the approved method AIUI) but, despite the metal corner
brackets between the strap cable and the chimney, the render has been
cracked at the chimney corners and has separated from the underlying
brick.

Is there any way to make this less likely, given that a cable would
probably need to be under a fair amount of tension to hold a satellite
dish firmly in place?


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

Windmill wrote:

From the street I can see a few cases where a TV mast has
been strapped to a chimney (the approved method AIUI) but,
despite the metal corner brackets between the strap cable
and the chimney, the render has been cracked at the chimney
corners and has separated from the underlying brick.

Is there any way to make this less likely, given that a
cable would probably need to be under a fair amount
of tension to hold a satellite dish firmly in place?

Presumably a bit of rubber sheet under the bracket should
spread the load and would be less likely to damage the render.

Havent tried it tho.

Maybe it would be better to have brackets with metal spikes on
the inside which would cut thru the render and hold on the brick.

Windmill wrote:

From the street I can see a few cases where a TV mast has been strapped
to a chimney (the approved method AIUI) but, despite the metal corner
brackets between the strap cable and the chimney, the render has been
cracked at the chimney corners and has separated from the underlying
brick.

Is there any way to make this less likely, given that a cable would
probably need to be under a fair amount of tension to hold a satellite
dish firmly in place?

Use of the brackets that uses packing strap instead of lashing wire?

http://www.blake-uk.com/stackstrap.aspx

Although I notice they now sell plastic corners for use with it, which
weren't available when I put mine up.

On Apr 6, 2:38*pm, (Windmill)
wrote:
From the street I can see a few cases where a TV mast has been strapped
to a chimney (the approved method AIUI) but, despite the metal corner
brackets between the strap cable and the chimney, the render has been
cracked at the chimney corners and has separated from the underlying
brick.

Is there any way to make this less likely, given that a cable would
probably need to be under a fair amount of tension to hold a satellite
dish firmly in place?

I think you'll find the cracking is due to the mast waggling in wind.
Esp. if it's a tall one.
The bracket is attached too high, there is insufficient weight of
brickwork above it to resist the tension forces generated.

A dish would be worse as it catches the wind.
Many chimneys are in bad state anyway, esp on older houses.

So, down to cowboy aerial fixers.

In message , Windmill
wrote
From the street I can see a few cases where a TV mast has been strapped
to a chimney (the approved method AIUI) but, despite the metal corner
brackets between the strap cable and the chimney, the render has been
cracked at the chimney corners and has separated from the underlying
brick.

Is there any way to make this less likely, given that a cable would
probably need to be under a fair amount of tension to hold a satellite
dish firmly in place?


Why do you want to fit a dish to a chimney? It's more suited to being
fitted to a wall.

If you cannot fit it to the satellite facing side of a house
http://www.wrightsaerials.tv/reference/dish-screened-by-roof.pdf

--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk

On Apr 7, 8:24*am, Alan wrote:
In message , Windmill
wrote

From the street I can see a few cases where a TV mast has been strapped
to a chimney (the approved method AIUI) but, despite the metal corner
brackets between the strap cable and the chimney, the render has been
cracked at the chimney corners and has separated from the underlying
brick.

Is there any way to make this less likely, given that a cable would
probably need to be under a fair amount of tension to hold a satellite
dish firmly in place?

Why do you want to fit a dish to a chimney? *It's more suited to being
fitted to a wall.

If you cannot fit it to the satellite facing side of a house
http://www.wrightsaerials.tv/reference/dish-screened-by-roof.pdf

--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk

I have seen them on masts. They have to have a clear "view " of the
satellite.

On 07/04/2012 08:55, harry wrote:
I have seen them on masts. They have to have a clear "view " of the
satellite.

Indeed. Ours has a clear view from just below first floor window level.

Andy

On Apr 7, 3:07*pm, Andy Champ wrote:
On 07/04/2012 08:55, harry wrote:

I have seen them on masts. They have to have a clear "view " of the
satellite.

Indeed. *Ours has a clear view from just below first floor window level..

Andy

Mine six feet off the ground. (We are on a hill)

In article , Andy Champ
scribeth thus
On 07/04/2012 08:55, harry wrote:
I have seen them on masts. They have to have a clear "view " of the
satellite.

Indeed. Ours has a clear view from just below first floor window level.

Andy

Ours are out in the back garden, you can't see them too well but they
can "see" the Sats..

As to chimney stacks on render perhaps thats in need to re doing as it
often needs. Chimney lashings very rarely harm a chimney unless grossly
under specified or with too large a windload imposed, more often they
hold them together;!...


--
Tony Sayer

harry writes:

On Apr 7, 3:07=A0pm, Andy Champ wrote:
On 07/04/2012 08:55, harry wrote:

I have seen them on masts. They have to have a clear "view " of the
satellite.

Indeed. =A0Ours has a clear view from just below first floor window level=
.

Andy

Mine six feet off the ground. (We are on a hill)

The place I was talking about is just outside a conservation area where
planning permission is required to fit dishes, TV aerials, etc. and I'm
guessing the neighbours wouldn't be too pleased by a dish on the wall
facing them.

So a dish on a mast strapped low down on a chimney and just above the
flat roof, all near the back, seems the best bet. (I think!)


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

tony sayer writes:

In article , Andy Champ
scribeth thus
On 07/04/2012 08:55, harry wrote:
I have seen them on masts. They have to have a clear "view " of the
satellite.

Indeed. Ours has a clear view from just below first floor window level.

Andy

Ours are out in the back garden, you can't see them too well but they
can "see" the Sats..

As to chimney stacks on render perhaps thats in need to re doing as it
often needs. Chimney lashings very rarely harm a chimney unless grossly
under specified or with too large a windload imposed, more often they
hold them together;!...

Thanks for that; it's reassuring.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

Andy Burns writes:

Windmill wrote:

From the street I can see a few cases where a TV mast has been strapped
to a chimney (the approved method AIUI) but, despite the metal corner
brackets between the strap cable and the chimney, the render has been
cracked at the chimney corners and has separated from the underlying
brick.

Is there any way to make this less likely, given that a cable would
probably need to be under a fair amount of tension to hold a satellite
dish firmly in place?

Use of the brackets that uses packing strap instead of lashing wire?

http://www.blake-uk.com/stackstrap.aspx

Although I notice they now sell plastic corners for use with it, which
weren't available when I put mine up.

I hadn't seen those, so I've got metal. May be a useful idea though.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

"Rod Speed" writes:

Windmill wrote:

From the street I can see a few cases where a TV mast has
been strapped to a chimney (the approved method AIUI) but,
despite the metal corner brackets between the strap cable
and the chimney, the render has been cracked at the chimney
corners and has separated from the underlying brick.

Is there any way to make this less likely, given that a
cable would probably need to be under a fair amount
of tension to hold a satellite dish firmly in place?

Presumably a bit of rubber sheet under the bracket should
spread the load and would be less likely to damage the render.

Havent tried it tho.

Maybe it would be better to have brackets with metal spikes on
the inside which would cut thru the render and hold on the brick.

Wouldn't that just crack the render?


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

Windmill wrote:

Andy writes:

http://www.blake-uk.com/stackstrap.aspx

I hadn't seen those, so I've got metal. May be a useful idea though.

Certainly easy to fit, and easy to tell that it's fitted properly if
(like me) you've not used lashing wire before and are worried if you get
it wrong it'll end up at ground level ...

With render it might be worth isolating the bracket from the
surface...

For small items "Rigifix" might work, they use a 10-12mm hole with a
plastic plug, then an allen key driven sleeve, then a standard metric
fastener (bolt) of M6-M8 can be screwed in preferably with some thread
lock compound.

For large items I would 25-38mm core drill via cordless through the
render to brick work. Cut some acetal round bar longer than the render
is thick, width chosen to fit within the core drilled holes and
drilled to take a stainless screw. Drill the brickwork for Fischer
SX10, fit together with stainless coach bolts. Silicone around the
render-spacer interface.

For a chimney, you run into several problems.
Insufficient mass above the fixing. Very tall chimney do flex with a
large aerial & gust loadings, or they crack resulting in the bracket
pulling a brick out of the chimney (brick shaped hole in stack
opposite, aerial & brick on roof). A crack in a very tall chimney will
propogate until the thing if lucky starts to twist making it obvious -
or simply plunge ground wards.

So perhaps find a wall.

"Windmill" wrote in message
...
"Rod Speed" writes:

Windmill wrote:

From the street I can see a few cases where a TV mast has
been strapped to a chimney (the approved method AIUI) but,
despite the metal corner brackets between the strap cable
and the chimney, the render has been cracked at the chimney
corners and has separated from the underlying brick.

Is there any way to make this less likely, given that a
cable would probably need to be under a fair amount
of tension to hold a satellite dish firmly in place?

Presumably a bit of rubber sheet under the bracket should
spread the load and would be less likely to damage the render.

Havent tried it tho.

Maybe it would be better to have brackets with metal spikes on
the inside which would cut thru the render and hold on the brick.

Wouldn't that just crack the render?

I was hoping it would just go thru the render.

If it wouldn't, you could drill the render where it will go.

"Windmill" wrote in message
...
harry writes:

On Apr 7, 3:07=A0pm, Andy Champ wrote:
On 07/04/2012 08:55, harry wrote:

I have seen them on masts. They have to have a clear "view " of the
satellite.

Indeed. =A0Ours has a clear view from just below first floor window
level=
.

Andy

Mine six feet off the ground. (We are on a hill)

The place I was talking about is just outside a conservation area where
planning permission is required to fit dishes, TV aerials, etc. and I'm
guessing the neighbours wouldn't be too pleased by a dish on the wall
facing them.

So a dish on a mast strapped low down on a chimney and just above the
flat roof, all near the back, seems the best bet. (I think!)

I just bolted mine down to the flat roof.

"Rod Speed" writes:

"Windmill" wrote in message
...
harry writes:

On Apr 7, 3:07=A0pm, Andy Champ wrote:
On 07/04/2012 08:55, harry wrote:

I have seen them on masts. They have to have a clear "view " of the
satellite.

Indeed. =A0Ours has a clear view from just below first floor window
level=
.

Andy

Mine six feet off the ground. (We are on a hill)

The place I was talking about is just outside a conservation area where
planning permission is required to fit dishes, TV aerials, etc. and I'm
guessing the neighbours wouldn't be too pleased by a dish on the wall
facing them.

So a dish on a mast strapped low down on a chimney and just above the
flat roof, all near the back, seems the best bet. (I think!)

I just bolted mine down to the flat roof.

Having seen too many 30,000 pound bills from the City for renewal of
slightly larger roof areas, I'd be very nervous about that.
(If those bills hadn't been split among 10, 20, or 30 flats, they would
have been killers).

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost