Velux install - what to look for?

[russlbuk]

Hi

I've got a roofer turning up to replace an original 1910 "velux" with a new much larger version an also install a new one elsewhere in the roof. These are being installed in our "lean-to" roof/loft space over the rear of our victorian terrace house.

We also need to cut through the purlin as this is in the way - how is this best supported?

I think I have the basics as a result of looking at this forum (obviously make sure there is a v solid frame around the hole), however what are the key things to look out for to make sure this is done properly (no I decided not to go building regs.... ).

From the other posts I've seen, the joists either side of the new holes should be doubled up with the quantity of ones removed. Do these need to run the full length of the existing joist (very difficult to install as we have a ceiling in the way) and do the horizontal "ceiling support" joists also need to be braced in the same way?

Thanks for any assistance in advance
Russ

 

[Alastairreid]

would double up joists either side of new install, probably full length depending on existing truss configuration. and double up on header /saddle.

1910 velux ? didnt know they made them then

 

[freddiemercurystwin]

We also need to cut through the purlin as this is in the way - how is this best supported?

You'll need to provide a bit more info as to how the purlin is supported, you can't just cut through a purlin and double up the rafters each side. The purlin is supporting the rafters.

 

[russlbuk]

It's the back part of the roof which connects to the main roof. Purlin appears to be joined by the current 'velux' and rests in the brickwork at one end of it. Not too sure about the other end to be honest, this must be joined with the corner of the main roof somehow...

No vertical supports for it that I have seen

 

[freddiemercurystwin]

So its supported by your brick wall at one end and something else the other end, probably a major supporting roof timber. You need to find out. Just because it has no other vertical supports still does not mean you can chop it in half. Purlins often span from party wall to party wall or other structural support without vertical supports in the middle. It doesn't make it any less structural. You'll either have to provide some useful info like a sketch or photos of the roof timbers or get an engineer up there. Are you sure its even a purlin, do you know what a purlin is or have you got your terminology a bit confused?

 

[russlbuk]

Hi - thanks....I'm fairly sure this is the purlin, however not an expert so could be wrong. Will try and upload a photo tomorrow....

I have 2 parts of the roof - one that runs from party wall to party wall and one that is perpendicular to this going out the back of the house alongside one of the party walls (think L shape roof). This timber/purlin is the one in the back part of the roof and is halfway up the roof rafters/supports. It's made up of 2 long pieces and rests in the brick wall at the end of the house & is nailed into the 'diagonal' main beam that joins the 2 roof parts (apologies, I am prob not explaining this at all well...it's a typical victorian terrace house with the bit out the back if that helps!)

I've also noticed that this beam appears to wedge/sit between the horizontal beams that hold up the ceiling and the roof joists - almost as if it is there to maintain the angle...

Thanks again

 

[JohnD]

I think the 1910 thing will be what we used to call a skylight.

A photo showing the roof timbers would help.,

 

[Nige F]

Hi

I've got a roofer turning up to replace an original 1910 "velux" with a new much larger version an also install a new one elsewhere in the roof. These are being installed in our "lean-to" roof/loft space over the rear of our victorian terrace house.


Thanks for any assistance in advance

Nine years too late for Victorian Gawd rest `er soul. Look out for too much flashing.

 

[freddiemercurystwin]

Make sure the fitter doesn't leave a gap between the rooflight and the tiles too!

 

[datarebal]

nothing like having confidence in your roofer.. why not read the instructions then show him how to do it...

 

[Alastairreid]

nothing like having confidence in your roofer.. why not read the instructions then show him how to do it...

 

[Nige F]

Get a proper chippy or even a structural engineer in, then let the roofer do the roofing