Velux window timber strengthening

[karltaylor1303@gmail]

Hi all looking for a bit of advise here.

Had a velux fitted in roof loft space at back of house.
3 bed semi 1940s
Velux fitted was 780 x 980 size about 32 kilo weight .
Over all i think about 14 to 16 tiles removed to fit it.
Velux is new bottom opening style .

Two rafters have had to be cut to fit it.
However i have noticed now after it had been fitted that the rafters each side of the velux have not been double up or sistered .
I was told it wasn't needed as window weight is less than tiles coming off the roof and the timbers in the roof are hard wood timbers.

Looking at the velux from inside the loft i can see it would be a straight forward job to simply bolt two timbers to the sides of the timbers where the velux is ? Or can i screw timbers on to them ?

As for the top and bottom i dont think i can do alot other than add timber in between the gaps or one full one on top ?

Any advice welcome?

The position of the velux on the roof is not the issue as only place it could be fitted. That is fine .

Its the strengthening of these timbers that is a possible issue or is it???

 

[karltaylor1303@gmail]

Total tile weight removed i think is around 50 kilo as each tile weight is approx 4 kilo

 

[Koolpc]

Waw, the position of that window is very odd.

 

[karltaylor1303@gmail]

Position is not important like i said previously. The concern is timber strengthening

 

[noseall]

I was told it wasn't needed as window weight is less than tiles coming off the roof

...and the weight of the tiles being supported on the two cut rafters (directly above the Velux), now being transferred to the neighbouring rafters?

They should be strengthened.

 

[Dereekoo]

.

 

[karltaylor1303@gmail]

So how would you suggest i strengthen this up as i csrnt take velux out to do it

 

[karltaylor1303@gmail]

View from outside.

Not alotvof tiles above velux .

So do i still need to strengthen inside.

As to position it was the only place it can go and was the smallest bottom opening design of velux available.

 

[karltaylor1303@gmail]

I am thinking two pieces of 3 x2 one at top above window frame and one on bottom screwed to rafters and two on sides . Bolted to exsiting or screwed??

 

[catlad]

No strengthening required there as its sat on the purlin.

 

[noseall]

No strengthening required there as its sat on the purlin.

The weakened bit above the purlin isn't.

 

[RandomGrinch]

Looking at the velux from inside the loft i can see it would be a straight forward job to simply bolt two timbers to the sides of the timbers where the velux is ? Or can i screw timbers on to them ?

Usually, when strengthening the rafters, the guidance is to double up on the whole unsupported length - i.e. if your skylight was above the purlin, the extra timber would run from purlin to ridge, not just where the Velux is.
In your case, as the Velux extends below the purlin, the strengthening may have to run the full length of the existing rafter - so I'm afraid this may not be as straightforward a task as you beleive.

Rarely, the existing structure may be strong enough to support the changes without additional strengthening; this could be where building control have a say - are your installers self-certifying to BC?

Building regulations: Rooflights - Roof - Planning Portal

Details of the planning permission and building regulation regimes for Roof in England

www.planningportal.co.uk

 

[karltaylor1303@gmail]

Yes self certifying. I am thinking now 4 sections of 3x 2 timber one either side top and bottom and one each side 2.4 metre length and two more 3 x2 one at top above perlin and window and one on bottom below perlin and window all screwed together with 6 x 8 screws .across each of the rafters .

This i think will be enough?

 

[catlad]

smallest bottom opening design of velux available.

Wrong! two sizes available that would have meant only crippling/cutting one rafter.

 

[karltaylor1303@gmail]

Two sizes of what ? Velux ?

No this is smallest top bottom opening design velux available as far as i am aware.

Because of this that was only place it can go and position