Trusses to ridge beam - who to call to design?

[Pabbles]

Hi everyone.

 

project no.2 on our new development is to redevelop an existing garage into a high-end home gym.

 

the garage is recently build and incredibly well made (cavity walls, oak framed double glazing, etc). It currently has a slate roof and traditional trusses.

 

We’re tackling this one straight away and the bit I’m stuck on is the roof design. The trusses don’t work due to height restrictions and we’ll need to switch to a ridge beam and rafters to give us the vaulted ceiling. We’ll also most likely include some roof lights - the existing slates will be stripped and relaid.

 

this is an embarrassingly simple question - but who do I call first?

 

we have an architect but it seems a waste to go via him as I’m sure he’ll outsource the calcs. Do we go straight to a structural engineer? Or do some roofing suppliers do this in house, like they do with trusses.

 

basically, I want a design that’s compliant with regs and is comprehensive enough for me to order materials before the roofers come out.

 

or… so I just call a roofer and expect them to self-certify it all?

 

(for context - in all the other works ongoing at the property I’ve been managing trades directly).

 

thank you.

[ETC]

5 minutes ago, Pabbles said:

Hi everyone.

 

project no.2 on our new development is to redevelop an existing garage into a high-end home gym.

 

the garage is recently build and incredibly well made (cavity walls, oak framed double glazing, etc). It currently has a slate roof and traditional trusses.

 

We’re tackling this one straight away and the bit I’m stuck on is the roof design. The trusses don’t work due to height restrictions and we’ll need to switch to a ridge beam and rafters to give us the vaulted ceiling. We’ll also most likely include some roof lights - the existing slates will be stripped and relaid.

 

this is an embarrassingly simple question - but who do I call first?

A structural engineer for the design of the ridge beam and rafters.

 

we have an architect but it seems a waste to go via him as I’m sure he’ll outsource the calcs. Do we go straight to a structural engineer? Or do some roofing suppliers do this in house, like they do with trusses. Don’t go to the roofers first they may have to out-source the ridge beam and rafter design and will pass the cost to you.

 

basically, I want a design that’s compliant with regs and is comprehensive enough for me to order materials before the roofers come out.

 

or… so I just call a roofer and expect them to self-certify it all?

Bad idea.

 

(for context - in all the other works ongoing at the property I’ve been managing trades directly).

 

thank you.

 

[nod]

Most truss companies have the software Just send them your drawing and they will come back to you with the pitch and loadings

 

[ETC]

5 minutes ago, nod said:

Most truss companies have the software Just send them your drawing and they will come back to you with the pitch and loadings

 

Not for a cut roof they won’t.

[nod]

6 hours ago, ETC said:

Not for a cut roof they won’t.

Ok

Dunscar will

 

If you can’t find somewhere local

Your Structual engineer will draw up a simple design 

Edited April 17, 2023 by nod

[Dave Jones]

8 hours ago, Pabbles said:

Hi everyone.

 

project no.2 on our new development is to redevelop an existing garage into a high-end home gym.

 

the garage is recently build and incredibly well made (cavity walls, oak framed double glazing, etc). It currently has a slate roof and traditional trusses.

 

We’re tackling this one straight away and the bit I’m stuck on is the roof design. The trusses don’t work due to height restrictions and we’ll need to switch to a ridge beam and rafters to give us the vaulted ceiling. We’ll also most likely include some roof lights - the existing slates will be stripped and relaid.

 

this is an embarrassingly simple question - but who do I call first?

 

we have an architect but it seems a waste to go via him as I’m sure he’ll outsource the calcs. Do we go straight to a structural engineer? Or do some roofing suppliers do this in house, like they do with trusses.

 

basically, I want a design that’s compliant with regs and is comprehensive enough for me to order materials before the roofers come out.

 

or… so I just call a roofer and expect them to self-certify it all?

 

(for context - in all the other works ongoing at the property I’ve been managing trades directly).

 

thank you.

 

depends on the span, if you can use span tables to keep building control happy then do it yourself.

 

if the spans means silly sizes of timber (££££) steel may be cheaper and you will need a n SE to design it.

 

Either way id get a trussed solution quoted first as they will be by fare the cheapest.

 

 

[Jenki]

Also look at camber trusses / raised tie truss etc., it will depend on heights etc. But a trussed roof will be far cheaper/ easier to install than traditional cut roof with steels. And the truss company will provide the calculations.

[Susie]

Agree on the trusses as cheaper. To save money we are going for a raised tie truss rather than fully vaulted we still get our roof windows velux and a high ceiling but gain a little top area for cables, MVHR or lights etc. 

two local companies have quoted and no need for an SE as BCO will be happy with what the truss company provide in calculations. 
 

 

[nod]

I’ve used raised tie and loose rafters in ours Loose is cheaper and I still spent a day doing the birds mouths on the trusses before  I even craned them up 

[ETC]

1 hour ago, nod said:

I’ve used raised tie and loose rafters in ours Loose is cheaper and I still spent a day doing the birds mouths on the trusses before  I even craned them up 

Doing the birds mouth on the trusses?

[ETC]

A cut roof (loose rafters and a ridge beam) should be cheaper.

[Bonner]

My supplier of the main roof trusses also provided the calcs and materials for a fully vaulted room - glulam beam and cut rafters

[nod]

1 hour ago, ETC said:

Doing the birds mouth on the trusses?

Yes 

Raised tie are thicker and allow for a cut In our case I cut them all 30 mil to nothing Just enough to stop them slipping 

[Carrerahill]

14 hours ago, Pabbles said:

Hi everyone.

 

project no.2 on our new development is to redevelop an existing garage into a high-end home gym.

 

the garage is recently build and incredibly well made (cavity walls, oak framed double glazing, etc). It currently has a slate roof and traditional trusses.

 

We’re tackling this one straight away and the bit I’m stuck on is the roof design. The trusses don’t work due to height restrictions and we’ll need to switch to a ridge beam and rafters to give us the vaulted ceiling. We’ll also most likely include some roof lights - the existing slates will be stripped and relaid.

 

this is an embarrassingly simple question - but who do I call first?

 

we have an architect but it seems a waste to go via him as I’m sure he’ll outsource the calcs. Do we go straight to a structural engineer? Or do some roofing suppliers do this in house, like they do with trusses.

 

basically, I want a design that’s compliant with regs and is comprehensive enough for me to order materials before the roofers come out.

 

or… so I just call a roofer and expect them to self-certify it all?

 

(for context - in all the other works ongoing at the property I’ve been managing trades directly).

 

thank you.

Why don't you just get a roof company to make you vaulted ceiling trusses? You get your roof made and they design it... 

[Mike]

When I did something similar I just used load tables for rafters and for the glulam beam. Done within the hour.