Deep brick reveals

[Construction Channel]

Howdy Everyone. 

 

I'm looking for ideas on how to "deal with" my external window reveals. this week i have been making the formwork to cast my cills which has brought back up an issue I was happily ignoring.

 

To be sensible I need to have the external edge of my windows and doors flush (ish) with my timber frame else all my heat is going to flow into my ventilated cavity.

 

this will leave roughly a 100mm cavity and then either 4 or 9 inches of brickwork. shown here badly

 

now I have never seen how anyone else has got over this with brick. it would be obvious for render or cladding but brick???????

 

only thing i have thought of so far was to try and emulate this look

 

initially, i thought to render it as they have but then I need to fix something to thin air over the cavity. then I considered using some kind of cement board as that would bridge the cavity well but it would involve painting so not going to happen, 

 

the current plan is to use a flush plastic fascia (windows will be white plastic) 

https://www.roofingsuperstore.co.uk/product/16mm-upvc-magnum-flat-fascia-board-cover-5m-x-150mm-white.html

 

I would mitre bond (superglue) it to the window and ct1 it to the brickwork, the plan would be to still leave some of the brick showing (30-40mm) to hide some of the "discrepancies" of the back wall. 

 

anyone else got any good ideas? 

 

I would normally just try it but I can't find anywhere without a delivery charge on "flush fascia" so if i buy any i will buy enough to do the lot

 

TIA 

 

Ed

[Ferdinand]

What is the look of your finished building?

 

Can you use a resinous hardwood to make the reveals plus span the cavity, and leave them little treated or untreated?

 

I am not able to recommend a particular wood, though. I am myself reflecting on what Timbers could support a canopy untreated. I even own a jousts-through-wall cantilevered canopy that has been there since 1970 and I do not know the timber type.

 

Alternatively can can you use one of the no maintenance cladding products such as Cedral or Thermowood?

 

Sorry .. missed the white plastic windows. Will leave post here.

 

Ferdinand

 

 

Edited November 15, 2017 by Ferdinand

[TerryE]

A bit late, but the other alternative is to mount your windows 50mm forward and surround them with PUR or mineral wool gap closers to act as side insulation. That way you'll only have a pointing gap between the windows and the brickwork.

 

If you use PUR then you might need to do a little surgery to allow them to slip over your edge wall tiles, but modern triple glazed window cassettes are reasonably deep. You can hang the windows on decent steel straps, but just make sure that you foam up properly; cut the excess of and silicon up the cut surface and face with decent airtightness tape.

[Russell griffiths]

Go and get a piece from wicks you can get it in single sheets there, if you can't find the profile you need run another shape(angle facia) through your table saw until you have the profile you need,

this is only a mock up so a bit of fettling may be needed until you get what you want. 

 

Have you thought of a completely contrasting colour maybe in grey, anthracite? 

How about getting a coloured flashing folded. 

 

What about a cement board and acrilic render, or eps and mesh and render. 

 

I wonder if the upvc will look a bit sterile and add a massive amount of white. 

[Construction Channel]

1 minute ago, Ferdinand said:

What is the look of your finished building?

 

hmmm, I think the only true answer would be "not sh1t"

essentially i need it to look like the old barn but that didn't have windows and all the surrounding building have just brick reveals, but they didn't have a cavity to hide

 

5 minutes ago, Ferdinand said:

Can you use a resinous hardwood to make the reveals plus span the cavity, and leave them little treated or untreated?

I like this, only thing would be the maintenance, I realise it would be minimal but i am trying to avoid any at all.

I will have to have a good hard think on this one though, Iv got oak for days, and wood is technically "what i do"  

 

7 minutes ago, Ferdinand said:

Alternatively can can you use one of the no maintenance cladding products such as Cedral

 

that was what i was thinking when i said "cement board"

problem is on the rear wall i need it to go to about 250mm to cover my cavity trays, i suppose they do a soffit that would work....

no.

It will need painting eventually and TBH i prefer either the wood or the plastic......

 

hmmm wood.

 

Thanks for the help

[Ferdinand]

Is there not a local supplier who will sell you just one piece as a test? Freefoam are everywhere.

 

If necessary cut it up in the car park?

 

 

Edited November 15, 2017 by Ferdinand

[Construction Channel]

1 minute ago, Ferdinand said:

Is there not a local supplier who will sell you just one piece? Free foam are everywhere.

 

If necessary cut it up in the car park?

 

 

TBH i will have to have a better look but the flush stuff doesn't seem that common

[Construction Channel]

11 minutes ago, TerryE said:

A bit late, but the other alternative is to mount your windows 50mm forward and surround them with PUR or mineral wool gap closers to act as side insulation. That way you'll only have a pointing gap between the windows and the brickwork.

 

If you use PUR then you might need to do a little surgery to allow them to slip over your edge wall tiles, but modern triple glazed window cassettes are reasonably deep. You can hang the windows on decent steel straps, but just make sure that you foam up properly; cut the excess of and silicon up the cut surface and face with decent airtightness tape.

 

all this time i have been happily ignoring the problem the plan was to fill the cavity with PUR say 100mm back and just mount the window in the brickwork like a normal person. but the more i have been looking at it the less i like it, 

 

the PUR would be just to close to the end of my cavity tray for my liking. 

[Ferdinand]

6 minutes ago, Construction Channel said:

TBH i will have to have a better look but the flush stuff doesn't seem that common

 

I would think that choosing planks of something which lasts 60 years as shingles or cladding would be in the ballpark.

 

Or what about whatever it is that wooden windowsills are made from? You may need your deal making skills, however, to make it affordable !

[Construction Channel]

15 minutes ago, Russell griffiths said:

Go and get a piece from wicks you can get it in single sheets there, if you can't find the profile you need run another shape(angle facia) through your table saw until you have the profile you need,

this is only a mock up so a bit of fettling may be needed until you get what you want. 

 

Have you thought of a completely contrasting colour maybe in grey, anthracite? 

How about getting a coloured flashing folded. 

 

What about a cement board and acrilic render, or eps and mesh and render. 

 

I wonder if the upvc will look a bit sterile and add a massive amount of white. 

I have got some fascia laying about I could cut the lip off. Ill have a mess about on the weekend in the daylight

 

i did consider anthracite but decided I would only be doing it for the sake of "fashion" so. no

 

also one of the main advantages of white plastic is it would help drag the light in hopefully, I have minimal windows to please the planners so any extra light I can get would be nice. 

 

I was also worried it may look sterile. but then there is a fine line between looking sterile and clean. I like the clean look, I may not maintain one but i like it

 

Im still not sure about cement board, It will need painting same as render eventually, 

 

plastic would match the window which is acceptable to me and wood would match the boards inside which is still ok, anything else i fear will look "out of place"

 

[Construction Channel]

4 minutes ago, Ferdinand said:

 

I would think that choosing planks of something which lasts 60 years as shingles or cladding would be in the ballpark.

 

Or what about whatever it is that wooden windowsills are made from? You may need your deal making skills, however, to make it affordable !

 

 you clearly didnt watch my videos about the chainsaw mill did you, 

 

if its wood it will be either oak or ash, (probably oak) and iv got both available by the forest load 

[Brickie]

So,just to clarify,you're positioning the frames flush with the inner leaf?

[Construction Channel]

That’s the plan at the moment. Flush with the outside edge of the timber frame. And before you say it I know the easiest way would have been to return the bricks but it’s far too late for that. 

[ProDave]

How about get a couple of 100mm thick sheets of wood fibre board. Cut into strips say 200 to 300mm wide and insert into the cavity. In effect an insulated cavity closer. Then render over that and the brick reveal to give the look you want.

 

Might need something to stick the wood fibre if it's not an interference fit into the cavity.

[Ferdinand]

8 hours ago, Construction Channel said:

 

 you clearly didnt watch my videos about the chainsaw mill did you, 

 

if its wood it will be either oak or ash, (probably oak) and iv got both available by the forest load 

 

Will remember that for when I need some.

 

I am sure there is a "Robin Hood in the Fens" legend .

 

Or perhaps not.

 

Edited November 16, 2017 by Ferdinand

[PeterW]

I’ve got some magnum soffit board hanging about if you want some to try it ..? It’s 9mm rather than the 16mm of the fascia

[Declan52]

1 hour ago, Construction Channel said:

That’s the plan at the moment. Flush with the outside edge of the timber frame. And before you say it I know the easiest way would have been to return the bricks but it’s far too late for that. 

The half brick you cut out will do the course above so it's only a full brick that gets slipped in to where the half brick was. Not a big job and will look much better than a piece of wood or plastic..

[TerryE]

10 hours ago, Construction Channel said:

all this time i have been happily ignoring the problem the plan was to fill the cavity with PUR say 100mm back and just mount the window in the brickwork like a normal person. but the more i have been looking at it the less i like it.  The PUR would be just to close to the end of my cavity tray for my liking.

 

The inner frame and the outer skin have different material and thermal characteristics so you will always get some form of shear movement between them, even if the odd mm.  If you mount your windows in the brick then this will always end up compromising the airtightness of the build.  If you mount the windows in the frame, immediately behind the brickwork then this shear line is at your outer weatherproofing mastic seal.

 

I don't understand your point about the PUR being close to the cavity tray.  You have to do this for two story buildings or higher to form a proper fire stop (remember Grendfell tower). 

 

10 hours ago, Construction Channel said:

I have minimal windows to please the planners so any extra light I can get would be nice.

 

I realise that it might be a bit late for you to do this but if you are mounting the windows forward, then putting a 60° angle on your inner reveals makes a huge difference in terms of light and impression.  This opens the windows form the inside and make them feel far less like a tunnel.  We've done this (and I've posted some pics to the forum too) and visitors to the house often comment on them --- always favourably.

 

See this for more details:

 

[Brickie]

Can you not insulate around the reveal & fix the frame in line with the cavity?

If there's enough play in the size of the frame maybe insulated plasterboard up the reveals too?

 

[Construction Channel]

thanks for all the responses guys.

Ill start at the top

8 hours ago, ProDave said:

How about get a couple of 100mm thick sheets of wood fibre board. Cut into strips say 200 to 300mm wide and insert into the cavity. In effect an insulated cavity closer. Then render over that and the brick reveal to give the look you want.

If im going to insulate the cavity I will use Celotex as I am already using it and will be a lot easier for me to get hold of. the issue i was thinking about with the cavity tray is this.

 

 

if i fill the red area with insulation moisture could potentially track along the blue line (realistically it would hit the plastic closure and probably be alright but it still worries me. other option would be to only put 100mm in but then it would have less insulation than the rest of the house and would be a "cold spot"

 

8 hours ago, PeterW said:

I’ve got some magnum soffit board hanging about if you want some to try it ..? It’s 9mm rather than the 16mm of the fascia

 

thats a very kind offer but iv got a bunch laying about too, my worry with soffit is the rounded edges wont look quite as crisp and it will be a lot harder to get the front edge nice and straight.

 

8 hours ago, Declan52 said:

The half brick you cut out will do the course above so it's only a full brick that gets slipped in to where the half brick was. Not a big job and will look much better than a piece of wood or plastic..

 

its big enough for me to not want to do it  also for some of the front windows i would have to corbel from a few courses down to get a header in the right place to cantilever,  iv only just laid all those bricks

 

7 hours ago, TerryE said:

The inner frame and the outer skin have different material and thermal characteristics so you will always get some form of shear movement between them, even if the odd mm.  If you mount your windows in the brick then this will always end up compromising the airtightness of the build.  If you mount the windows in the frame, immediately behind the brickwork then this shear line is at your outer weatherproofing mastic seal.

 

even if i fit them in the brick skin (which is what i would ideally like to do) i would still not actually fix to the bricks, i would fit them with straps back to the timber frame which should get over this problem.

 

7 hours ago, TerryE said:

I don't understand your point about the PUR being close to the cavity tray.  You have to do this for two story buildings or higher to form a proper fire stop (remember Grendfell tower). 

 hopefully my fantastic illustration will explain better. 

 

8 hours ago, TerryE said:

I realise that it might be a bit late

 

yes it is   i considered flaring my openings, especially my veluxes but unfortunately that is about as far as it went,

 

7 hours ago, Brickie said:

Can you not insulate around the reveal & fix the frame in line with the cavity?

If there's enough play in the size of the frame maybe insulated plasterboard up the reveals too?

i could probably get away with a little, maybe the thinner thermal plasterboard. 

 

Thanks again for all the help, i really need to mess about with some fascia in the daylight and see how i feel about it, if it does look as hateful as i fear it might ill just have to bring the window forward, insulate the cavity and have a slightly colder spot. not the end of the world i suppose...

[SteamyTea]

I might be miles off here, but can't you get some GRP made up (or do it yourself, Faye is a clever girl), easy enough to get the sizes you need with the right (simple) tooling.

[TerryE]

6 hours ago, Construction Channel said:

hopefully my fantastic illustration will explain better. 

 

I still don't understand the issue.  How do you control the ingress of moisture above the lintels?  In our case the lintels extend  ~150mm beyond the end of the frame and we have a secondary DPC and weep vents above each lintel so this forms an "umbrella" over both the windows and gap closers.  In principle you could still get some moisture ingress along the mortar stop between the brickwork and the window, but (i) this is sealed with a flexible sealer bead anyway and (ii) the preferential path is straight down. Though, in our case we fitted the windows into the frame on the last day of the frame erection and subsequently put the skin up to the frame which made things  a lot easier.  In terms of the gap closer, the one we used was mineral wool in a heavy duty PVC sleeve so there isn't any entrance path for trickling water.  They were exposed to the elements for about six months and didn't show any signs of getting wet, so I doubt that we'd have any problems once protected by the skin. 

 

We can have chat on Thursday.