My house was built in the 80,s by Winpeys. It has the common Flink
Trusses.

The span front to back is 8M there are 8 trusess across the house
spanning 4.5M.
Im looking to convert the loft into a habitable room over a longish
period of time as money permits.

What im looking for is the stages you need to go through to remove the
spars of the trusses.

Thats the first bit i want to do.

Does any one have any pictures of a conversion from start to finish.



thanks


garry

You need building regulations approval and before that the services of a
structural engineer.

Peter Crosland

"GarryNutter" wrote in message
ups.com...
My house was built in the 80,s by Winpeys. It has the common Flink
Trusses.

The span front to back is 8M there are 8 trusess across the house
spanning 4.5M.
Im looking to convert the loft into a habitable room over a longish
period of time as money permits.

What im looking for is the stages you need to go through to remove the
spars of the trusses.

Thats the first bit i want to do.

Does any one have any pictures of a conversion from start to finish.


http://www.internode.co.uk/loft/index.htm Would be a good start.
The owner is a regular poster here.

Steven Campbell wrote:
"GarryNutter" wrote in message
ups.com...
My house was built in the 80,s by Winpeys. It has the common Flink
Trusses.

The span front to back is 8M there are 8 trusess across the house
spanning 4.5M.
Im looking to convert the loft into a habitable room over a longish
period of time as money permits.

What im looking for is the stages you need to go through to remove the
spars of the trusses.

Thats the first bit i want to do.

Does any one have any pictures of a conversion from start to finish.


http://www.internode.co.uk/loft/index.htm Would be a good start.
The owner is a regular poster here.

I don't believe that was a modern truss roof.

MBQ

GarryNutter wrote:
My house was built in the 80,s by Winpeys. It has the common Flink
Trusses.

The span front to back is 8M there are 8 trusess across the house
spanning 4.5M.
Im looking to convert the loft into a habitable room over a longish
period of time as money permits.

What im looking for is the stages you need to go through to remove the
spars of the trusses.

My sister had this done and they basically built a whole new roof
structure out of very substiantial timbers paralle to the trusses and
tied to new timbers and steels in the floor. Only then were the old
trusses removed.

MBQ

wrote:

http://www.internode.co.uk/loft/index.htm Would be a good start.
The owner is a regular poster here.


I don't believe that was a modern truss roof.

Nope it wasn't... having said that, some of the same approach may be
possible. A trussed roof would probably have less cross members and tie
beams to get in the way, and this may allow the introduction of the
floor joists between existing trusses without actually changing any of
them at that stage.

It would obviously be fiddly work however since you would be working
among all the extra wood of the trusses. A 4.5m span is within the
realms of possibility for a wood beam (or a flitch beam certainly). You
would probably need more holes through the roof however to get them in
there since any rotation or moving them about once in the loft is going
to be pretty difficult!

The harder bit is making sure you have adequate support in place before
you start trimming out the webbing of the trusses.


--
Cheers,

John.

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Thanks everyone, for the help. John your site is a aladins cave of
information. Could i ask how do you arrive at the position of the Knee
Wall.

As i only have 8 rafters i was going to sister a furthur 150*50 to each
rafter, and tie them in at the top, to make a triangle. Could i get
away with 150*50, coudnt find any information on the web of the correct
size for this.


thanks

garry

John Rumm wrote:

The harder bit is making sure you have adequate support in place before
you start trimming out the webbing of the trusses.

Is it not on then to remove the additional matchstick forest from just
one truss, and add glued screwed additional depth to all 3 sides to
bring it upto required strength, and once done move onto the next one?


NT

Garry Nutter wrote:

As i only have 8 rafters i was going to sister a furthur 150*50 to each
rafter, and tie them in at the top, to make a triangle. Could i get
away with 150*50, coudnt find any information on the web of the correct
size for this.

I've more often seen 2x4 used on old houses. But you need to put in
whatever the regs say now, for some reason.


NT

Garry Nutter wrote:

Thanks everyone, for the help. John your site is a aladins cave of
information. Could i ask how do you arrive at the position of the Knee
Wall.

The wall is a load bearing wall and takes the place of the purlin that
was removed from the front of the roof slope. So its position is chosen
to be roughly mid span of the front rafters and not that far from the
original purlin location. In reality it could go a few feet either way -
its location is not that critical.

As i only have 8 rafters i was going to sister a furthur 150*50 to each
rafter, and tie them in at the top, to make a triangle. Could i get
away with 150*50, coudnt find any information on the web of the correct
size for this.

To answer questions like this you need to do (or get done) some design
calculations based on the anticipated loadings. In many respects you
would probably find it easier to build a new floor without connecting it
in any way to the existing trusses. You could also take the same
approach to supporting the roof, or you could look at ways of reusing
some of original truss components. The difficult thing with the trusses
is that they are only structurally strong in their complete form. They
don't have much rigidity the moment you chop bits out of them (although
they are probably strong enough to hold up the facias and soffits by
themselves ;-)

150*50 is going to be well undersized for a floor at that span. It is
probably more heavy than required for rafters though. Having said that
it does depend on the type of roof and its pitch, and the spacings of
the rafters. Note there is no need to maintain the same spacing as the
trusses - you could insert more rafters if you wanted.

--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

wrote:

The harder bit is making sure you have adequate support in place before
you start trimming out the webbing of the trusses.


Is it not on then to remove the additional matchstick forest from just
one truss, and add glued screwed additional depth to all 3 sides to
bring it upto required strength, and once done move onto the next one?

That might also work. Not having done a trussed roof I am not famillier
with the range of methods used to deal with them. Building a new roof
supporting structure in parallel to the old would seem like a safe
option, but may well be more work than is actually required if you can
reuse some of the existing stuff. It will also depend a bit on what sort
of converison you are doing since in many cases you won't be keeping the
triangle shape of the trusses due to dormers etc.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
wrote:

The harder bit is making sure you have adequate support in place before
you start trimming out the webbing of the trusses.

Is it not on then to remove the additional matchstick forest from just
one truss, and add glued screwed additional depth to all 3 sides to
bring it upto required strength, and once done move onto the next one?

That might also work. Not having done a trussed roof I am not famillier
with the range of methods used to deal with them. Building a new roof
supporting structure in parallel to the old would seem like a safe
option, but may well be more work than is actually required if you can
reuse some of the existing stuff. It will also depend a bit on what sort
of converison you are doing since in many cases you won't be keeping the
triangle shape of the trusses due to dormers etc.


Strikes me it would fit well with the idea of doing a bit as and when,
as it wouldnt disrupt the ceiling, and wood could be used that could be
carried up through the hatch. So one could do one truss at a time with
no time constraints or mess. New wood added could be end jointed with a
router and glued and screwed in place.


NT

wrote:

Strikes me it would fit well with the idea of doing a bit as and when,
as it wouldnt disrupt the ceiling, and wood could be used that could be

With regard to the ceiling, you could also achieve the same result if
you have new floor joists in place and then added noggings between them
also nailed to the truss to support the span of the base of the truss. A
bit like I did for the old ceiling joists after removing their tie beam
he

http://www.internode.co.uk/loft/images/rearjoists.jpg

This would also help retain some of the benefit of not completely
coupling the new floor to the existing ceiling (from a noise
transmission point of view if nothing else).

carried up through the hatch. So one could do one truss at a time with
no time constraints or mess. New wood added could be end jointed with a
router and glued and screwed in place.

You may have fun trying to produce the calcs to convince a BCO that the
result is structurally sound. They seem rather wary of any joints more
complex than a nail these days! ;-)


--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

I'm sorry i think i have confused everybody with my terms and what i
want to do.


The Grand Plan Hope Ive explained better this time.

Due to money restrictions i would like to convert the loft to Habitable
space eventually.

To-do this i will need to get a structural engineer to calculate to
beam sizes to support the roof and a new floor.
Ive consulted the structural guy and Ive got a set of drawings,
dimensions and structural calculations for the two beams.

The beams are 152*152*37 UC steal. I think the 37 is the weight.
On top of this beam will be 150*75 wood plate to support the knee wall
and something to hang the joists of via joist hangers.
Joists are specified as 175*50, to cover a span of 15ft, these are on
400 centers.

I plan to do it in this order

1st get the steel beams in and the joists between,
get some flooring laid in the joists to work off.
Reinforce the roof rafters
Build the knee wall
Check every things okay

Cut out the old timbers
Stop praying.


Questions
Looking at Johns site
http://www.internode.co.uk/loft/superstructure.htm 4th picture from the
bottom. John how did you arrive at the size and position for these
timbers which link the roof rafters together?

As i have fink trusses "w" shape made from 4.5 by 1.5 inch timber,
i plan on screwing or bolting and gluing together a 150*50 timber to
the side of every roof joist.
Do you think this will be strong enough ?

That should do it for now possible further questions later.


Thanks

Garry

Garry Nutter wrote:

I'm sorry i think i have confused everybody with my terms and what i
want to do.

The Grand Plan Hope Ive explained better this time.

OK, perhaps an ASCII art layout of the beams may help us to visualise
things...

or even something like:

http://www.internode.co.uk/temp/beam-layout.gif

1st get the steel beams in and the joists between,
get some flooring laid in the joists to work off.

You may have difficulty getting flooring in there with all the truss
webbing in place... then again that depends a bit on the type of trusses
you have.

Reinforce the roof rafters
Build the knee wall
Check every things okay

Cut out the old timbers

Oh that is the fun bit... (in fact the most fun I have had with a
chainsaw in ages ;-)

Questions
Looking at Johns site
http://www.internode.co.uk/loft/superstructure.htm 4th picture from the
bottom. John how did you arrive at the size and position for these
timbers which link the roof rafters together?

What, this one?:

http://www.internode.co.uk/loft/images/roofsupport.jpg

Firstly to get some bearings on the shot, you are looking up toward the
ridge of the roof, where the front slope meets the flat roof of the rear
dormer.

The rafters under the slope are spaced at 400mm centres - this was to
match the existing rafters. Some of them are old, some were new where
the original ones were not long enough to meet the extended ridge beam
(remember it used to be a hipped roof). (In the photo you can only see
new ones).

The spacing of the roof joists was also 400mm (chosen deliberately) so
that each one could meet a rafter. Note that this is a slightly non
typical way of doing it. In many cases you would simply stick a steel in
under the ridge to pick up all the rafters. We did not need to do this
however because I was making two rooms that were to have a dividing wall
not far from the ridge position. Hence the dividing wall actually takes
the load of the ridge using the ends of the flat roof joists in
cantileaver.

The size of beam required for the roof joist was calculated in Superbeam
using a uniform loading due to the flat roof of 0.6kN/m (warm deck with
three layers of hot bonded felt - so not that heavy). And a further
point load of 0.48kN per joist exerted by the front roof rafter on the
end of each flat roof joist at a distance of 0.8m from the supporting wall.

So looking at the side :

0.47
| Point load
v
_________________0.6kN / m__________________
/ \ Uniform load

##############################################
##############################################
##############################################
| |
v v
0.67kN downforce on 2.21kN downforce on
read dormer wall partition wall



As i have fink trusses "w" shape made from 4.5 by 1.5 inch timber,

Like the third one down?:

http://www.phillipsbuildingsupply.co...y_designs.html


i plan on screwing or bolting and gluing together a 150*50 timber to
the side of every roof joist.
Do you think this will be strong enough ?

Note that your rafters are already comparable to my 4x2" rafters and are
not as thin and skimpy as the matchstick wood they seem to make some
trusses from. Hence I would expect if you stick a dwarf wall where the
short arm of the W is, and a steel beam under the ridge, you may need no
further strengthening of the rafters.

That should do it for now possible further questions later.

;-)


--
Cheers,

John.

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