I pulled down a sagging ceiling in one of my bedrooms at the weekend
(as one does). Above it, the joists spanning the room are bowed and
need replacing.

The joists are nailed into the rafters beneath the oak beams that run
the length of the house on either side (they are not attached to the
beams).

What I would like to do is replace the joists with ones above the oak
beams (to expose the beams and create more space in the bedroom).

Bad ASCII art of the side view follows.

What I have (The O's are the oak beams);
/\
/ \
/ \
/O O\
/----------------\
/ \
| |
| |
| |


What I want;
/\
/ \
/________\
/O O\
/ \
/ \
| |
| |
| |

I have 2 bedrooms in this elevation with a brick wall in the middle
(upto the height of the oak beams). The walls are stone to the height
of the beams with brick above. A brick extension runs off a hip in
the middle of the house

The joists are 3"x1 1/2", the rafters are 3"x2", Both are about 10' in
length.. They are spaced about 1' apart along the roof.

Can I do what I want? Is there a good book? Is is diy or do I need
an expert?

Any other information that I should post here?

Thanks,

John

In article ,
(John Seed) writes:
I pulled down a sagging ceiling in one of my bedrooms at the weekend
(as one does). Above it, the joists spanning the room are bowed and
need replacing.

The joists are nailed into the rafters beneath the oak beams that run
the length of the house on either side (they are not attached to the
beams).

It may not have been apparent, but the joists are nomally rather
structural -- they stop the roof spreading (rafters doing the splits)
and sliding off the wall plates (your oak beams) or pushing the walls
out with the weight of the roof.

--
Andrew Gabriel

In an earlier contribution to this discussion,
John Seed wrote:

I pulled down a sagging ceiling in one of my bedrooms at the weekend
(as one does). Above it, the joists spanning the room are bowed and
need replacing.

The joists are nailed into the rafters beneath the oak beams that run
the length of the house on either side (they are not attached to the
beams).

What I would like to do is replace the joists with ones above the oak
beams (to expose the beams and create more space in the bedroom).

Bad ASCII art of the side view follows.

What I have (The O's are the oak beams);
/\
/ \
/ \
/O O\
/----------------\
/ \
|
|
|


What I want;
/\
/ \
/________\
/O O\
/ \
/ \
|
|
|

I have 2 bedrooms in this elevation with a brick wall in the middle
(upto the height of the oak beams). The walls are stone to the height
of the beams with brick above. A brick extension runs off a hip in
the middle of the house

The joists are 3"x1 1/2", the rafters are 3"x2", Both are about 10' in
length.. They are spaced about 1' apart along the roof.

Can I do what I want? Is there a good book? Is is diy or do I need
an expert?

Any other information that I should post here?

Thanks,

John

It's probably ok, if the oak beams are fully supporting the roof. However,
there is a possibility that the joists are an integral part of the
structure, and are required to prevent the roof from spreading.

You would do well to consult a structural engineer before removing them.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

Can I do what I want? Is there a good book? Is is diy or do I need
an expert?

It looks possible to me, but you need to get a structural engineer to
calculate it. In particular, the joists may currently be used to reduce
spreading loads from the roof. It must be ensured that the new joist
position with less leverage is still sufficient for that purpose. Even if
not, there's probably a way through, such as using hidden metal rods or
flitch beams or something.

As to whether the work is DIYable, that depends on your experience.
Personally, I'd get a builder in to do the structural stuff, but would
probably put up the plasterboard, insulation and electrics myself. (I'd get
a plasterer in to skim it).

Christian.

In article ,
John Seed wrote:
Can I do what I want? Is there a good book? Is is diy or do I need
an expert?

I'd certainly get in a structural engineer. Shouldn't cost a fortune.

--
*Eschew obfuscation *

Dave Plowman London SW 12
RIP Acorn

Excellent responses, thanks.

Any recommendations for a structural engineer in Cheshire/Staffordshire/Shropshire?

Thanks again,

John

"John Seed" wrote in message
om

Excellent responses, thanks.

Any recommendations for a structural engineer in Cheshire/Staffordshire/Shropshire?

Don't be silly. Recommending a use of them is not the same as having
ever used them.

The oak -if oak they be, are purlins. The wall plate rests on the wall.
The joists pulling the rafters together will occur above or below the
purlins but the way the rafters bend with resultants will change.

Instead of tending to arc out they will tend to arc in. Getting good
photos before you do the job will not only get you more confidant help
but provide you with a record of stability over the years you remain
there.

Whatever you decide, there was something already wrong with the building
when you had to pull the ceiling down. I suspect a previous owner did
something non-U with the roof. Get lots of lights in there and a good
photographer.


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

"John Seed" wrote in message
om...
I pulled down a sagging ceiling in one of my bedrooms at the weekend
(as one does). Above it, the joists spanning the room are bowed and
need replacing.

The joists are nailed into the rafters beneath the oak beams that run
the length of the house on either side (they are not attached to the
beams).

What I would like to do is replace the joists with ones above the oak
beams (to expose the beams and create more space in the bedroom).

Bad ASCII art of the side view follows.

What I have (The O's are the oak beams);
/\
/ \
/ \
/O O\
/----------------\
/ \
| |
| |
| |


What I want;
/\
/ \
/________\
/O O\
/ \
/ \
| |
| |
| |

I have 2 bedrooms in this elevation with a brick wall in the middle
(upto the height of the oak beams). The walls are stone to the height
of the beams with brick above. A brick extension runs off a hip in
the middle of the house

The joists are 3"x1 1/2", the rafters are 3"x2", Both are about 10' in
length.. They are spaced about 1' apart along the roof.

Can I do what I want? Is there a good book? Is is diy or do I need
an expert?

Any other information that I should post here?


What is the age of this house. Roof design has changed over the years and
the places where forces are applied changed with it. I've done something
with a very similar end result in my house and it looks fabulous, but the
joists run parallel to the purlins so there was far less problems.

The main problem with modifying your arrangment is that the stresses on the
new joints will be higher than the current arrangement. Also there is
unfortunately a possibility of the roof moving as the new arrangement
settles causing some work to be needed there as well.

Do you REALLY want to do this ?

What is the age of this house.
I'm guessing at least 150 years, though I think the roof (except the
beams) is 20th century

Do you REALLY want to do this ?
Only if it's not TOO EXPENSIVE.

Thanks,

John

The oak -if oak they be, are purlins.
Obviously, I'm just assuming oak.

Getting good photos before you do the job will not only get you more confidant help
but provide you with a record of stability over the years you remain
there.
OK, I've got "some" photos;

http://www.photobox.co.uk/album/albu...c_album=727733

But what's my next move?

Thanks,

John

In message , John Seed
writes
The oak -if oak they be, are purlins.
Obviously, I'm just assuming oak.

Getting good photos before you do the job will not only get you more
confidant help
but provide you with a record of stability over the years you remain
there.
OK, I've got "some" photos;

http://www.photobox.co.uk/album/albu...c_album=727733

But what's my next move?

Post them somewhere that doesn't require the viewer to log in ?

--
geoff

"geoff" wrote in message


OK, I've got "some" photos;
http://www.photobox.co.uk/album/albu...c_album=727733
But what's my next move?

A bungalow I think.
Make sure the family gets out before that move takes place

Post them somewhere that doesn't require the viewer to log in?




--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

Post them somewhere that doesn't require the viewer to log in ?

I hadn't clicked the "public" button;

http://www.photobox.co.uk/public/det...c_album=727733

In an earlier contribution to this discussion,
John Seed wrote:

Post them somewhere that doesn't require the viewer to log in ?

I hadn't clicked the "public" button;

http://www.photobox.co.uk/public/det...c_album=727733


Hm! Why would anyone *want* to expose any of that lot?
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square" wrote in message
...
In an earlier contribution to this discussion,
John Seed wrote:

Post them somewhere that doesn't require the viewer to log in ?

I hadn't clicked the "public" button;

http://www.photobox.co.uk/public/det...c_album=727733


Hm! Why would anyone *want* to expose any of that lot?

oh, I could see why - the OP just wants to expose the purlins, not
necessarily the whole roof space. Would give additional height to the
bedroom as well. Presumably the exposed rafter ends would be covered and
made good with plasterboard.

What puzzles me is why the joists have sagged - is this likely to be just
the weight of the ceiling pulling down on them? I thought that ceiling
joists would normally be in tension - keeping the rafters from spreading and
maintaining the integrety of the walls. The purlins should presumably
supported at each end by the walls, but there couldn't be any chance that
these joists are, for some reason, taking the weight of these purlins,
causing them to sag? If that was the case then something seems to me to be
very wrong, and removing the joists could have very serious short term
consequences!

In any case, this is non-trivial stuff potentially affecting the structural
stablility of the house, and if I was the OP then I'd want to get the (paid)
advice of a structural engineer as to whether it is possible to proceed, and
if it is then the specs for the new joists and how they should be fixed to
the rafters.

Armed with this info I don't see any reason why a competent DIYer following
proper practise for the work couldn't tackle the job...

--
Richard Sampson

email me at
richard at olifant d-ot co do-t uk

In message , John Seed
writes
Post them somewhere that doesn't require the viewer to log in ?

I hadn't clicked the "public" button;

http://www.photobox.co.uk/public/det...c_album=727733

That looks like a serious bit of work to undertake.

Honest opinion ? forget it.

--
geoff

On 15 Jun 2004 07:22:14 -0700,
(John Seed) wrote:

Excellent responses, thanks.

Any recommendations for a structural engineer in Cheshire/Staffordshire/Shropshire?

Thanks again,

John

I am using Alun Jones in Mold, I have been happy so far. I know he
goes out to those areas.

As you are likley to be into Building Regs teritory, this won't be a
cheep job. The building Regs guys cost you about 10% of the build
cost, then you have a few hundered each for the architect to draw the
pictures, and the enginner to do the sums .......

Rick

On 16 Jun 2004 15:11:27 -0700,
(John Seed) wrote:

The oak -if oak they be, are purlins.
Obviously, I'm just assuming oak.

Getting good photos before you do the job will not only get you more confidant help
but provide you with a record of stability over the years you remain
there.
OK, I've got "some" photos;

http://www.photobox.co.uk/album/albu...c_album=727733

But what's my next move?

Thanks,

John

I would guess its gonna cost you a couple of grand, so decide if its
worth it ........ Thats the next move

You might find the house is like mine, built without the cross
members, so they can be removed. I can work this out cause of the age
of the woods in the building, most are very old, the cross members are
much newer, definatly not orignal. Also inside the loft you can still
see the orignal celing going right up to the point. A bit of digging
arround may yeald some results .......

Rick

"RichardS" noaccess@invalid wrote in message


What puzzles me is why the joists have sagged I thought that ceiling
joists would normally be in tension - keeping the rafters from spreading and
maintaining the integrety of the walls.

I don't think they have sagged. The level is not very long and the house
is old. Rough sawn timber will shrivel a little between the knots. (I
bet the high spots are a metre apart -just the length to throw that
level out. Try a sting line underneath, right along them.)

Armed with this info I don't see any reason why a competent DIYer following
proper practise for the work couldn't tackle the job...

Me too neither.

The joists are classically marked by laths used with lime mortar and
that was the problem. They had come away from the grounds.

The purlins are 7 or 8 by 2 1/2s or 3's and will relocate the stresses
very well when you shift the joists. You can reuse them.

Put battens along each edge to take the plasterboard. Make sure that
they are exactly 400 or 600 gaps so that you can use the boards
economically.

Put rockwool above each as you go.

Don't forget to make a loft hatch.

Put 1" ply under the purlins along the rafters tight up against
everything and

Use longish ring nails or screws and tight fitted fillets top and
bottom.

When you have finished; remember to clean, sand and paint or stain them
all before you start.



--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

If his joists are running parallel to the purlins he had a good reason
to use a structural engineer.

(He can sue the pants off the fool if he lives long enough.)

It won't cost you much more than the time you put into it and a few
sheets of board and some insulation.

Edit to an earlier post:

If you put the plasterboard on top of the newly positioned joists, you
will not need to bother with the battons.

Take the time to put a light in the roof space. Space the joists
according to the board you use. Ply would be better than plasterboard as
you can then utilise the attic.

If you put the ply under the purlins as suggested you might want to put
lights in it, so put the wire behind them as you go and drill through
for the feeds.




--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

Hm! Why would anyone *want* to expose any of that lot?

oh, I could see why - the OP just wants to expose the purlins, not
necessarily the whole roof space. Would give additional height to the
bedroom as well. Presumably the exposed rafter ends would be covered and
made good with plasterboard.

Exactly.

What puzzles me is why the joists have sagged - is this likely to be just
the weight of the ceiling pulling down on them? I thought that ceiling
joists would normally be in tension - keeping the rafters from spreading and
maintaining the integrety of the walls. The purlins should presumably
supported at each end by the walls, but there couldn't be any chance that
these joists are, for some reason, taking the weight of these purlins,
causing them to sag?

No. The joists aren't touching the purlins. Some of the joists
actually have "scoops" cut out of them in order to stop them from
touching the purlins.

In any case, this is non-trivial stuff potentially affecting the structural
stablility of the house, and if I was the OP then I'd want to get the (paid)
advice of a structural engineer

Happy to do that

Armed with this info I don't see any reason why a competent DIYer following
proper practise for the work couldn't tackle the job...

It looks so straightforward - cutting bits of wood and nailing them in
(I know it's a bit more involved than that in reality).

Thanks,

John

It looks so straightforward - cutting bits of wood and nailing them in
(I know it's a bit more involved than that in reality).

Yes, like making sure you don't remove the old ones before enough of the new
support is in! Also, planning how you are going to get the old joists out of
the roof space and the new joists in. You may need to remove some roof
covering and use some sort of crane or hoist, unless you are planning to
reuse the shortened old joists.

Christian.

What puzzles me is why the joists have sagged I thought that ceiling
joists would normally be in tension - keeping the rafters from spreading and
maintaining the integrety of the walls.

I don't think they have sagged. The level is not very long and the house
is old. Rough sawn timber will shrivel a little between the knots. (I
bet the high spots are a metre apart -just the length to throw that
level out.

I think you could be spot on there. The removed ceiling definitely sagged.

Try a sting line underneath, right along them.)

OK

It won't cost you much more than the time you put into it and a few
sheets of board and some insulation.

That's what I was thinking/hoping.

Thanks again for your help,

John

"John Seed" wrote in message
om

It won't cost you much more than the time you put into it and a few
sheets of board and some insulation.

That's what I was thinking/hoping.

What is holding the purlins up at the inside ends? You should have
posted that. The only reason you have purlins on a 10 ft span is that
they are doing something interesting with the dogleg in the roof.



--
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"Christian McArdle" wrote in message
t

Yes, like making sure you don't remove the old ones before enough of the new
support is in! Also, planning how you are going to get the old joists out of
the roof space and the new joists in. You may need to remove some roof
covering and use some sort of crane or hoist, unless you are planning to
reuse the shortened old joists.

He could take out 3 or 4 and put them up cleaned. Putting 3/4 ply on
them means he won't need insulation. Take out another set and start
loading out. If he puts a strip of 1" ply under the purlin tight to
both the wall plate and the purlin he could get all his sheets up on a
calm, dry day without sagging the roof or losing slates and then bobs
your uncle.

I'd use screws as they will cause less jarring than nails. If I didn't
have them already, I'd buy a cheap circular saw and a second battery
screwdriver. One for predrilling and one for screwdriving.
Paint or stain the boards before sending them up as this will save half
the job later and prevent them getting dirty.


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

What is holding the purlins up at the inside ends?

They go straight into the wall.

The only reason you have purlins on a 10 ft span is that
they are doing something interesting with the dogleg in the roof.

You mean the hip extension? Again I think you could be right.

I've posted more photos showing the purlins going into the wall and
views of the purlins on both sides of the extension;

http://www.photobox.co.uk/album/albu...c_album=727733

Thanks,

John