Height of a fascia.

[epsilonGreedy]

I need to decide how high my fascia should be, is there an industry default height on which I can then base any aesthetic adjustments?

 

My fascia will most likely be 1" thick wood painted in an offwhite with black metal gutters.

 

Other details: Dark grey slate, 30 degree pitch hipped roof, 8" to 10" eave overhang.

 

We are aiming for the Jane Austen vintage look and I use Frogmore Cottage (2nd photo) for a heritage point of reference.

 

A retired architect in the village stopped for a chat last year and recommended a more shallow fascia, he added that a deep fascia is a tell-tale modern feature driven by the need for thick attic insulation.

 

[Big Jimbo]

I think that if you aim for 170mm high facia, you should end up with the look you are after.

[epsilonGreedy]

7 minutes ago, Big Jimbo said:

I think that if you aim for 170mm high facia, you should end up with the look you are after.

 

 

Ok so maybe I should calculate the fascia height as a ratio of the eave overhang i.e. about 75% of the overhang.

 

Just need to check this also works for the gutter mount and drop from the slate edge..

[bassanclan]

From the look of that the fascia is very small, only just deeper than the gutter but the soffit very deep 400mm or so

[Iceverge]

A bugbear of mine. 

 

We had 98mm rafter truss tails. 

 

Over and over I stressed to keep the fascia slim. 

 

Despite all this the. Roofers and fascia guys went from my 150mm drawings of fascia to 170 to 195 and eventually 225 is what we ended up with. "its the way we always do it m8"

 

Banging my head against a brick wall. 

 

Keep them as slim as possible is my take for the most elegant look. You can cut an angle from the rafter tails to help too. 

 

 

 

 

Edited March 8, 2021 by Iceverge
Add photo

[epsilonGreedy]

23 minutes ago, Iceverge said:

A bugbear of mine. 

 

We had 98mm rafter truss tails. 

 

Over and over I stressed to keep the fascia slim...

 

 

I am burning a lot of brain cycles on this single detail, one problem is there are few examples locally. As Kevin McCloud would say the local vernacular is barebones eaves, no overhang with guttering hanging off brackets embedded in the facing bricks.

 

Does your photo show the 225mm end result?

 

Another benefit of slim fascias is that this will exhibit more of the expensive flat fan arches above the upper window.

[epsilonGreedy]

1 hour ago, bassanclan said:

From the look of that the fascia is very small, only just deeper than the gutter but the soffit very deep 400mm or so

 

 

I will cut some spare osb board, paint with the linseed test pot that arrived last week and mock up one corner.

[Russell griffiths]

How high has your brickwork been taken, the shallower the facia the more bricks on show, have they come up high enough. 

Your facia needs to project up the correct amount to provide seating for the first row of slates. 

[Oz07]

Try and get it to course in with the brickwork. Decide how high a kick you need above rafters. With conc tiles you want about 50mm but you can do 25 with 25 over fascia vents. Then the face of your rafters. 

 

I think a 150mm fascia would be pretty slim by the time you put the guttering on and the tiles or eaves trays hang down a couple of inch

[Iceverge]

On 08/03/2021 at 14:28, epsilonGreedy said:

 

I am burning a lot of brain cycles on this single detail, one problem is there are few examples locally. As Kevin McCloud would say the local vernacular is barebones eaves, no overhang with guttering hanging off brackets embedded in the facing bricks.

 

Does your photo show the 225mm end result?

 

Another benefit of slim fascias is that this will exhibit more of the expensive flat fan arches above the upper window.

Sorry I didn't see this until now.

 

Yes 225mm it looks ok as we fitted deepish guttering. The trouble is though its just not perfect! 

 

Just do it as thin as you can manage and it'll look well

[epsilonGreedy]

On 08/03/2021 at 17:10, Russell griffiths said:

How high has your brickwork been taken, the shallower the fascia the more bricks on show, have they come up high enough. 

 

 

Yes defo high enough,  I probably wasted money on a superfluous course. The brickie did ask for eave design clarification.

 

On 08/03/2021 at 17:10, Russell griffiths said:

Your facia needs to project up the correct amount to provide seating for the first row of slates.

 

 

I need to settle on an exact amount of upward projection here, people talk about giving a kick to the first row of tiles though I am not sure this is the right design feature for a 30 degree pitch with hip ends. Another forum member fitting slates had to add an extra wooden strip onto his fascia to overcome a calculation error. I assume I just need 25mm to match the batten height plus a touch more to ensure no slate rattle in the wind. I am going for under soffit ventilation hence no thick over the fascia ventilation plastic to account for.

 

  

[epsilonGreedy]

On 12/03/2021 at 19:50, Oz07 said:

Try and get it to course in with the brickwork.

 

 

Ok this is an extra subtlety I had not thought about. Is soffit to brick course sync an aesthetic point?

[Russell griffiths]

1 hour ago, epsilonGreedy said:

 

Ok this is an extra subtlety I had not thought about. Is soffit to brick course sync an aesthetic point?

Bit late now,

you can sit your soffit on top of your last course of bricks, this saves you having to cut soffit and creates a nice edge. 

 

I would do a bit of mocking up, grab half a dozen metre lengths of batten and batten out the first 4-5 rows of slates. 

Allowing for any detail courses at the eaves, you will soon see how high the facia needs to be buy the way the slates sit, then get a gutter bracket and some soffit, after two hours of messing you will have a better idea. 

[epsilonGreedy]

Ok trying to turn this into a formula:

 

Fascia height =

 

Projection above rafter top to support first row of slates (minimum = height of roofing battens) - Minus thickness of plastic eave tray support. (25mm)

 

Plus

 

Drop to top upper lip of gutter which is likely determined by downward projection of the lower lip of the eave support tray (??mm)

 

Plus 

 

Gutter cross section height (80mm)

 

Plus

 

Required gradient drop for the longest run of guttering (35mm)

 

Plus

 

Clear exposed fascia below gutter which is an aesthetic feature (0mm)

 

Plus

 

(Special in my case) Height of 45 degree bevel trimmed off lower edge of wooden fascia (5mm) 

 

Total = 145mm

[Russell griffiths]

Plastic eaves support tray is 2-3mm thick not 25mm. 

As I believe you said no vents on top of facia. 

[TonyT]

you can get away with having a smaller drop on the guttering if it helps take it closer to a stock timber dimension.

 

 

[SuperJohnG]

Hmm, I'm doing my fascia detail just now to order stuff in prep for kit going up. Reading this makes me think I've messed up 

 

I had the SIPS kit manufacturer cut the ends of the kit plumb, so I could attached a Fascia directly to it, but it's a 219mm thick roof panel, then I need  25mm counter batten, then 22mm sarking, then it's slates. 

 

Looking here, the plumb cut it 310mm, plus my 25mm and 22mm for sarking and batten, is this going to look ridiculous? How else shoudl I have done it?. I was hoping I could attach fibre cement fascia directly and make life easy. 

 

Edited May 4, 2021 by SuperJohnG

[Marvin]

Hi Super JohnG.

As the over hang is outside the thermal envelope, looking at the problem the only thing I can think of to do,  if the fascia is too tall, is to cut part of sloping soffit side horizontal however I'm not sure this wouldn't cause you other problems.

Hopefully someone comes up with a better answer.

 

Good luck.

M

[joe90]

3 hours ago, Marvin said:

Hi Super JohnG.

As the over hang is outside the thermal envelope, looking at the problem the only thing I can think of to do,  if the fascia is too tall, is to cut part of sloping soffit side horizontal however I'm not sure this wouldn't cause you other problems.

Hopefully someone comes up with a better answer.

 

Good luck.

M

This is a good idea, it would give you a flat surface to fix a soffit too as well.

[SuperJohnG]

4 hours ago, joe90 said:

This is a good idea, it would give you a flat surface to fix a soffit too as well.

Make sense, just seems a major pain to do. I'd need to cut it then add a timber and that that is SIPS it's all insualtion. 

 

Architect suggested the below which works. Just an extra step. Also doesn't deal with verges which is impossible really as panels are 219 thick. 

 

[joe90]

Yes, cut sip to required height by removing the bottom pointy bit, hack out the insulation enough  to put noggins between OSB sides both vertically and horizontal to fix facia and soffit too, you just need to work out what facia height you actually want!

[Nick Laslett]

On 04/05/2021 at 23:35, SuperJohnG said:

Hmm, I'm doing my fascia detail just now to order stuff in prep for kit going up. Reading this makes me think I've messed up 

 

I had the SIPS kit manufacturer cut the ends of the kit plumb, so I could attached a Fascia directly to it, but it's a 219mm thick roof panel, then I need  25mm counter batten, then 22mm sarking, then it's slates. 

 

Looking here, the plumb cut it 310mm, plus my 25mm and 22mm for sarking and batten, is this going to look ridiculous? How else shoudl I have done it?. I was hoping I could attach fibre cement fascia directly and make life easy. 

 

Hello @SuperJohnG, what did you end up doing? My Thermohouse roof boards, with battens currently make 460mm flat fascia edge. I’m thinking of cutting off some of the EPS up to the embedded metal C section. Don’t really have a good photo of this to hand. 
 

 

[SuperJohnG]

I used 10mm capping board. Works fine. Will add photos tomorrow.