I am replacing a sash window at the rear of my house with french doors.
I have looked to see if there is a lintel and found (in common with the
rest of my house) a concrete lintel that has been cast in-situ. Can I
assume this is going to be ok or should I get a structural engineer to
look at it. The lintel spans about 1.5 m.

wrote:
I am replacing a sash window at the rear of my house with french doors.
I have looked to see if there is a lintel and found (in common with the
rest of my house) a concrete lintel that has been cast in-situ. Can I
assume this is going to be ok or should I get a structural engineer to
look at it. The lintel spans about 1.5 m.

I have recently had this done to a rear dining room window that now has a
patio door, and the existing lintel was left in place. If you are not
widening the opening then as far as I am aware there is no need to replace
the lintel. If you are widening the opening then that's a different matter.

"Phil Anthropist" wrote in message
...
wrote:
I am replacing a sash window at the rear of my house with french doors.
I have looked to see if there is a lintel and found (in common with the
rest of my house) a concrete lintel that has been cast in-situ. Can I
assume this is going to be ok or should I get a structural engineer to
look at it. The lintel spans about 1.5 m.

I have recently had this done to a rear dining room window that now has a
patio door, and the existing lintel was left in place. If you are not
widening the opening then as far as I am aware there is no need to replace
the lintel. If you are widening the opening then that's a different
matter.

This is true but the problem you commonly find is that the window line is
too high for the doors to look nice inside, where you want them the same
hight (roughly) as the internal doors. This was the problem I found anyway.
Mine had a timber lintel and I just installed a Catnic lintel underneath
after the window had been knocked out, packed up to the original lintel and
then carried on curtting the opening etc.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

"Bob Mannix" wrote:
This is true but the problem you commonly find is that the window line is
too high for the doors to look nice inside, where you want them the same
hight (roughly) as the internal doors. This was the problem I found
anyway. Mine had a timber lintel and I just installed a Catnic lintel
underneath after the window had been knocked out, packed up to the
original lintel and then carried on curtting the opening etc.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Fortunately height wasn't a problem with my patio door, it is the same
height as the box sash frame that it replaced, and roughly the same height
as the internal doors. We wanted the new opening to let in the maximum
amount of air and light.

I was planning on using a fanlight to make up the additional height.
What worries me a little though is how much structural support is being
given to the opening by the existing sash frame which has a large
central strut.

Phil Anthropist wrote:
"Bob Mannix" wrote:
This is true but the problem you commonly find is that the window line is
too high for the doors to look nice inside, where you want them the same
hight (roughly) as the internal doors. This was the problem I found
anyway. Mine had a timber lintel and I just installed a Catnic lintel
underneath after the window had been knocked out, packed up to the
original lintel and then carried on curtting the opening etc.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Fortunately height wasn't a problem with my patio door, it is the same
height as the box sash frame that it replaced, and roughly the same height
as the internal doors. We wanted the new opening to let in the maximum
amount of air and light.

wrote in message
ps.com...
I was planning on using a fanlight to make up the additional height.
What worries me a little though is how much structural support is being
given to the opening by the existing sash frame which has a large
central strut.


You didn't say how big the "cast in situ" concrete lintel was. If it is at
all substantial it will be taking the weight. The corbelling effect reduces
the apparent load on such lintels. If you can shift the central strut
easily, it ain't doing any support. If, on the other hand, it won't
move......


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

wrote:
I was planning on using a fanlight to make up the additional height.
What worries me a little though is how much structural support is being
given to the opening by the existing sash frame which has a large
central strut.

That's tricky. My understanding is that window frames should not be load
bearing, except for bay windows which may include two pillars as part of the
frame, but the presence of a large central strut is suspicious. Three
suggestions:

1.) Post a photo on the web so that we can see the structure
2.) Take a photo or drawing to a reliable/trustworthy local builder and/or
double glazing company (the surveyor, not salesman) and ask them if you were
to have the conversion done would they also have to insert a bigger lintel
3.) Ask for a site visit and estimate

Just that it has been cast in-situ. ie the concrete has been poured on
site using formers etc. Also the sash window frame has a substantial
vertical strut in the centre, which could be load bearing. I haven't
taken the window out yet, but if other areas of the house are anything
to go by the top of the window frame will have been used as the bottom
former for the lintel. ie the window was probably in place when they
poured the concrete to form the lintel.

wrote:
wrote:
I am replacing a sash window at the rear of my house with french doors.
I have looked to see if there is a lintel and found (in common with the
rest of my house) a concrete lintel that has been cast in-situ. Can I
assume this is going to be ok or should I get a structural engineer to
look at it. The lintel spans about 1.5 m.

almost certainly be ok, though it probably wont meet new build regs, eg
due to thermal bridging. Is there a specific reason to think its
inadequate?


NT