Roof extension with a terrace

[OliverCarter]

I intend on extending my top floor apartment. I will build an extra floor and replace the roof, then on one side I will have a terrace. I've been a carpenter for over 10 years but so far never managed a job as big as this.

I've been told by an experienced builder that it's actually very simple. I could pre-fab some timber frames in a workshop, strip my roof completely, then crane lift the frames up. Assemble them then put the roof back on.

I'm still unsure about the steps to take. Plus I'm not sure about the best methods for waterproofing the terrace. I have no doubt that I am capable of the job, it's just getting things organised and executed. Any advice would be greatly appreciated.

 

[pinenot]

The thing about taking the old roof off is how it's constructed, fixed and roof covering.
Firstly it will have to be manufactured trusses, stick built roofs would be incredibly difficult to brace for that type of operation. And secondly, you would have to figure out a lifting plan, point through the roof where the sling would go, lifting spreaders to take the opposite load bearing the roof was designed for etc. The rest is easy, this is how timberframe building roofs are often done i.e. built on the ground and craned into place. And the walls are straight forward build, hoist up to storey and fixed and braced etc.
You will have to be familiar with timberframe building and how to marry two building styles together, but no big shakes...pinenot

 

[freddiemercurystwin]

Haha easypeasy! Don't forget the structural engineer to prove your handrails won't fall off and the host of other Building Regs to get through. Oh yea don't forget the panning permission either! Yea easypeasy!

 

[pinenot]

Oh yea of little faith ...pinenot

 

[OliverCarter]

Firslty, thank you for your feedback.

The roof is extremely shallow, I stand higher than the apex. It's also constructed very easily. (by the way, I live in the Netherlands now so things are done a bit differently here) There are just 20mm boards nailed to the purlin, then roof felt lays straight on top of them.
I would strip the felt off, then the boards, leaving the roof open. Once I've cut the roof components out I will be ready to position my walls. But what are they to sit on? Just stick them straight onto the internal block? Or should I anchor a wall plate down first, maybe some lead flashing?
Once the walls are crane lifted on I will build the rood on site. It won't be difficult. I think it may be flatter than the existing roof.

Overall my biggest concern is getting in on then realising I have damp appearing in mine or the neighbours house. Something that could have been addressed at an earlier time.

Thanks

 

[pinenot]

Certainly needs to have a wall plate anchored to the existing brick. I would probably use chemi anchors and dpc between brick and timber. as for lead flashing etc. are the existing brick walls cavity solid or what? ...pinenot

 

[OliverCarter]

It's a pretty old building so I believe the walls are solid. Thanks for your advice.

 

[pinenot]

So, how are you cladding the timber frame, matching brick/stone, timber cladding or what? ...pinenot

 

[OliverCarter]

The cladding will have to be something that fits in with the surroundings, I'm assuming the government will want us to have either brick or terracotta tile.[/quote]