Preferred positioning of Velux windows?

[hammerswinger]

Hi,
can I ask you guys if you have a preference of where you fit a velux windows in a lean to roof that will have a vaulted ceiling.

Is it just a case of centralising the velux in the center of the span or would you off set it a little, say closer to the outside wall of the lean to roof.

I appreciate that this is a personal preference thing but I just wondered if
by positioning the windows slightly closer to the outside wall it would fool your eye that it was in the center, sort of how door hinges look right even though the bottom one is higher up the door!

Thanks.

 

[freddiemercurystwin]

Generally try to get an even distribution of light in the room which usually suggests (across the ceiling) a central position if only one is being fitted and of course rafter centres must be considered. Height ways generally the lower down the roof they go the more light will be able to enter the room. Personally I prefer them about a third-half way up rather than in the centre.

 

[hammerswinger]

Thanks for your reply,

I'll be fitting three 78 x 118cm windows so they have been spaced across the room width just where they need to be, it's just the height up the roof that got me thinking, at the moment they are placed central in the span (in the center of the internal rafter length measurement) & I'm not 100% sure if it looks right to my eye, I think they maybe would look better if the were moved towards the outside wall by 100mm or so.... (say the bottom double trimmer width)

Decisions....Decisions....


Thanks.

 

[9494jones]

Hi there. I recently fitted 3no electric Roto roof windows in a new extension and gave careful consideration to where they should be placed. The first was an equal spacing across the span of the roof although I could have gone for a combination/bank of 3 or even 2 +1 if that makes sense. I also placed them fairly central going up the roof but this was not before checking how the light would be distributed inside the property.

One of the biggest issues here is creating the best light splay inside the room. Often is the case that builders/joiners/roofers trim out the opening and put the top/bottom trimmers/noggins too close to the window which means that when you plasterboard you get a beam of light inside the propoerty whereas if you set the trimmers/noggins away from the top/bottom of the window, you get a better light splay/distribution into the property.

Ultimatley, I believe it is down to you.

 

[hammerswinger]

Hi,
I had my Velux windows delivered today & after looking at the fitting instructions (which are very poor in my opinion) I'm very confused and think I may have to alter the openings I have made
I asked at the builders merchant what size opening would be required for the size window I was ordering (78 x 118cm) and they found out for me, I was told that the window size quoted is the opening size required, I made the opening 79 x 119cm just to give a slight fitting tolerance, however when looking at the picture instructions that came with the windows it looks like the opening should be 40 - 60mm wider than the window in width & 45mm in height.

Can any one advise if I will be ok with the size openings I have or will I have to enlarge them?

Thanks.

 

[9494jones]

Hi there. The window frame size is NOT the opening size. With my Roto windows, the external frame size was 740wx980H. On the width you leave 35mm either side to allow for insulation...a must.....that is probably what the 40/60mm is with these windows. As for the height, this differs depending on the pitch of the roof and it is a guide to where to put your top and bottom noggins/trimmers. The idea is to create as much light in the room as possible and so if you place your noggins too close to the window, you limit the amount of light splay. May I suggets you try Roto as they are great windows.

 

[hammerswinger]

Hi,
Just had a look at Roto windows & they look very good but I already have the Velux windows

It looks like I may have to alter the size of the openings I've made unless someone tells me different?

The Velux fitting instructions are rubbish, just a series of graphics like pictures, the type you would get with a self assembly kitchen unit.
The only insulation I can see around the window is in the form of an BDX kit, this is an additional kit and I think this may fill the 40-60mm gap that the instructions show?

I would post a link to the instructions but for some reason links to the velux site don't work

Maybe I can fill the small gap I will have between the window and the Rafters / Trimmers with expanding foam?

I understand what you mean about positioning the trimmers & light spread.


Thanks.

 

[OwainDIYer]

Height up the roof - top of the window should be at head height inside. This gives the best chance of actually being able to look out of the window.

However if it's a fire escape window then there are rules where they go.

 

[datarebal]

They have to be postioned to make sure there are NO cut tiles under the windows or the flashings will not fit correctly. you can only adjust tile gauges a cetain amount and keep the tiled roof looking good.

In this case you have been committed as the openings are formed. but guessing where the fascia height will be you might be ok..

However if the flashings seem not to work well.. then.. i told you so..

 

[hammerswinger]

Hi,
Ok I see what you mean regarding cut tiles below the window.

With all the factors that need to be considered, roof tile size, size and positioning of the window, how would a roofer proceed from scratch if coming to construct my roof? would all of these factors be worked out before the openings were made?

Another factor is that the ceiling is going to be vaulted so the windows need to be spaced across the width evenly so it looks correct from inside, so how do you avoid small cut tiles at the sides of the window, it could work out that you have small slithers of tile at the sides.

I can't see how at roof construction stage you can possibly figure out all of the factors that are involved, the only way I can see to position the window to avoid problems would be to build the roof with no openings then lay out the tiles then positioning the windows, this way you could try to avoid small tiles either side of the window or cut tiles below, but then the equal spacing across the width may suffer.

Can someone explain the procedure to me from the start of building the roof?

Thanks.

 

[seasickstevie]

With regard vertical position decisions, I line up the bottom edge of the flashing apron in line with bottom edge of tiles. Otherwise you get excessive flashing showing, or insufficient overlap on tiles below.

I don't think (relatively) thin strips of tile at the sides are anything yo worry about, as the flashing should take care of that. And if the flashing kit seems insufficient, you can always use additional lead beneath the Velux stuff.
I usually find Velux supply more than enough flashing.

 

[seasickstevie]

I agree very much with 9494jones about the noggins being moved away to give plenty of 'splay'. To some extent the same can be said for the sides, as to the window can be fitted to 'substantial' battens fixed above your roof timbers. Some additional timber can always be fitted under these battens spanning the opening later if you feel it's needed.

Also, as already said, you need to allow space for insulation around the opening over the timbers.

It might seem odd at first, but I feel you're best making the opening too big rather than too small.

 

[datarebal]

The positioning of the window up the roof slope can be simply worked out once the first rafter is cut..Simple.

the 780x118 is the exact external size of the frame,
Doing what you have done adding 10mm all round will work with not problems. there will be slight light loss

There is plenty of apron flashing provided you read the instructions and go within tolerences.

Umm strip of lead below the window... it can be done but a bit mickey mouse.. but thats may opinion.

Cuts either side of a window can not allways be avoided but very small cuts can.

 

[seasickstevie]

Umm strip of lead below the window... it can be done but a bit mickey mouse.. but thats may opinion.

Maybe I didn't make it clear, but the suggestion of lead was beneath the soakers at the sides of the windows if narrow strips of tile create a problem, not "below the window"

Never thought of lead being 'Micky Mouse' before but hey-ho!

 

[hammerswinger]

...Cuts either side of a window can not allways be avoided but very small cuts can.

I assume to avoid small cuts the window would be moved to the left or right, I can't really do this as the 3 windows need to be spaced evenly over the vaulted ceiling area.

It's not the end of the World if I have to move the openings up or down a bit to avoid a cut tile below the window.

As the roof of the extension is at a pitch of about 20 degrees I don't think the light splay issue will have too much of an effect, that said if I'm moving the openings I could position the bottom trimmer so that the ceiling at the bottom of the window would end up vertical, but if the trimmer is moved away from the window what does the window sit on, the diagram in the instructions seem to show it just sitting on a roof batten ?

I was told that the rafters either side of the windows and the trimmers have to be doubled up, if the trimmers are moved away from the window do they still need to be doubled up?


Thanks to everyone for all of the advice



Cheers.