Hire the best Home Extension Experts

2nd story timber wall plate on external brick wall, does it need damp course?

Results 1 to 41 of 41
  1. #1
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default 2nd story timber wall plate on external brick wall, does it need damp course?

    hi guys,

    firstly apologies if the terminology is wrong (feel free to correct it!)

    as the title states, does a 2nd story wall plate (which will have the floor joists bearing on them) resting on the first story external brick wall need damp course?
    i can only assume it would as if the bricks get drenched with rain, the water may be soaked into the timber and over time rot..

    or am i missing something?

  2. #2
    4K Club Member
    Join Date
    Nov 2008
    Location
    nsw
    Posts
    4,227

    Default

    Quote Originally Posted by melton2 View Post
    hi guys,

    firstly apologies if the terminology is wrong (feel free to correct it!)

    as the title states, does a 2nd story wall plate (which will have the floor joists bearing on them) resting on the first story external brick wall need damp course?
    i can only assume it would as if the bricks get drenched with rain, the water may be soaked into the timber and over time rot..

    or am i missing something?
    It sounds a bit strange to have that situation happening, the plate should be landing on an inner skin of cavity brickwork were a dpc wouldn't be needed or engaged piers where there would be dpc on those piers under a beam.
    regards inter

  3. #3
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    the ceiling joists are sitting on the inner skin of brickwork, as well as having electrical wiring as well as the brickwork not being level... i.e they are a mess to work with...

    thats why i chose the option of to bypass the internal plate, and build the second story on top of the outer brick work which has been bricked up level all the way around the house (i had to brick up 3 courses to make the outer skin in height with the inner skin after i dropped the eaves)...

    i dont see it being an issue in terms of getting wet from rain as it will be cladded as well as having sarking, but only from rising water from the brick work if it got drenched, hence the dampcourse...

    can you see any possible issues/problems with that??

  4. #4
    Je pense, donc METRIX's Avatar
    Join Date
    Apr 2012
    Location
    Sydney North
    Posts
    9,697

    Default

    It's not an issue with damp etc that I would be concerned about, but more that the external skin is only face brick, and the internal skin is where loads should be put.

    Your situation does not sound correct, do you have some pictures to show what has been done ?

  5. #5
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    here are some photos.
    the first picture you can see the ceiling joists, and roof rafters which have been cut to accomodate the external brick height extension

    the second and third photo will show you what i mean by them not being level (different pattern of brickwork needed)

    i want my floor joists to finish with the external bricks so the wall goes straight up from bottom floor to top floor, and doesnt dip in (like i have seen on many double story extensions as the additional brickwork needed like in my case was avoided.)

    but if im resting the floor joists (300x45 LVL) on the internal plate, and have the floor joists cantilevering over the external bricks without support, how would they take the load of the external walls and roof (skillon, colorbond)? i know its not much of a cantilever (about 170mm) but i would definitely want support under those, hence the external plate with dampcourse

    both internal and external brick walls were built on the same footings, same bricks used for internal and external, all tied into each other

    i still dont see an issue apart from the damp problem i thought about (which as stated is probably not a concern)





    i want the wall to sit flush like this (plate height not to scale, not sure how much height difference i need)
    not like this which i have seen


    any opinions?
    Attached Thumbnails Attached Thumbnails wp_20130427_001.jpg   wp_20130427_004.jpg   wp_20130427_005.jpg   wall2.jpg   wall3.jpg  


  6. #6
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Just one thing I would consider is cantilevering the floor joists over the existing topplate. What is going on top, cladding!
    [




    i want the wall to sit flush like this (plate height not to scale, not sure how much height difference i need).

    any opinions?[/QUOTE]

  7. #7
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by phild01 View Post
    Just one thing I would consider is cantilevering the floor joists over the existing topplate. What is going on top, cladding!
    [/QUOTE]

    i dont particularly want to pack every floor joist as i have mentioned that the internal brick wall is not level all the way around the house...

    secondly, there is electrical hovering over some areas of the internal plate.

  8. #8
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Bit hard to comment about structural stability though your question relates to damp coursing. This will depend on what is going up there. The cladding and how it is flashed.

  9. #9
    4K Club Member
    Join Date
    Nov 2008
    Location
    nsw
    Posts
    4,227

    Default

    It is industry practice to support the structure off the inner leaf of brickwork, that means the joists would cantilever over the cavity to the line of the outer leaf of masonry, the only thing I can think of that would hamper your idea of reversing it would be the durability of the exposed outer leaf of masonry, ie the exposure of the mortar to the elements means that it will have a shorter lifespan than the inner leaf, with greater loads on it there could be greater risk of an unexpected collapse in the future, whereas if normal building convention was followed there would be nill risk.
    regards inter

  10. #10
    Je pense, donc METRIX's Avatar
    Join Date
    Apr 2012
    Location
    Sydney North
    Posts
    9,697

    Default

    I don't particularly want to pack every floor joist as i have mentioned that the internal brick wall is not level all the way around the house...

    secondly, there is electrical hovering over some areas of the internal plate.
    Not sure why you don't want to pack out the floor joists (I know, you mentioned they are all over the place this is normal), It is standard practice to pack and level under the new joists when doing 2nd story additions, there is no short cuts for this step.

    Using a laser the leveling and packing out only takes a few hours, and gives you a very flat secure surface for your floor and 2nd story to sit on.

    Don't worry about any wires these won't interfere with the packing, you just make the packing 20mm shorter in these sections and the wire just runs along side the packing.

    I am not a fan of not building to standard industry practices, as for the future if a problem presents itself, and the outer skin needs removing either intentionally or un intentionally then your construction will be different to almost everyone else's and can present unexpected problems, when we come across construction like what you are proposing, you know straight away it was not done by a reputable builder, but a home owner.

    We do a bit of insurance work, we did a job where a car had run into the corner of a house, doing a lot of damage to the external brick wall (collapsed majority of one wall and a portion of the other ), there was slight damage to the internal wall (broke 2 studs and dislodged a third), the house was still structurally sound and had emergency minor temporary propping inside to ensure it's stability until the insurance approved it's repaired.

    In your case there would be the real possibility of major damage to the upper story / roof or possible partial collapse in this situation as your addition would be resting on the outside skin, as has been said here previously not industry standard practice.

    My suggestion, If you really want to rest it on the outside walls, then pack up the internal skin top plate as a backup, I'm not sure who is approving your build but doing what you intend to do should have been pointed out as not the normal way of doing this, I know our certifier would not approve this construction method.

  11. #11
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    intertd6 and METRIX, thanks for the reply...

    i never thought about possible issues with the outer skin...

    well now the outer skin is level all the way around, i will place new plates on them for levelness, and then pack the internal skins to the new height... that would be much easier as i dont have to keep checking heights as i know that they are resting on something which is level..

    i was going to call my certifier on Monday about it, but with this issue in my head it would be bugging me all weekend... atleast now i have a resolution

    cheers for the replies guys.. much appreciated...

  12. #12
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Your certifier might still have a groan about this. Why not place the top-plate on the outer skin just to achieve levels temporarily and as you say pack joists on inner skin, strap/secure these, and then just remove the temporary top-plate (be sure it can slide out freely). I suspect you are using something like blue-board above!

    Quote Originally Posted by melton2 View Post
    intertd6 and METRIX, thanks for the reply...

    i never thought about possible issues with the outer skin...

    well now the outer skin is level all the way around, i will place new plates on them for levelness, and then pack the internal skins to the new height... that would be much easier as i dont have to keep checking heights as i know that they are resting on something which is level..

    i was going to call my certifier on Monday about it, but with this issue in my head it would be bugging me all weekend... atleast now i have a resolution

    cheers for the replies guys.. much appreciated...

  13. #13
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by phild01 View Post
    Your certifier might still have a groan about this. Why not place the top-plate on the outer skin just to achieve levels temporarily and as you say pack joists on inner skin, strap/secure these, and then just remove the temporary top-plate (be sure it can slide out freely). I suspect you are using something like blue-board above!

    i thought about that but as im cladding that part of the house i need the first row of cladding to be nailed into something, and if the joists are 50-70mm off the brickwork, the cladding cant be nailed into anything and would leave the bottom half of the first row unattached really....

    if i leave the plates there, then i can use that to nail the cladding to it...

    i cant see any issue with leaving the plate there if the joists are bearing on the internal brickwork now...

    but if anyone can see issues, please let me know!

  14. #14
    Je pense, donc METRIX's Avatar
    Join Date
    Apr 2012
    Location
    Sydney North
    Posts
    9,697

    Default

    You would need to block out the ends of the joists anyway, and then vapour barrier all the timberwork, depending on what cladding you are going for vinal is attached into a starter strip which would be attached to the brickwork and usually comes in 230mm height, so you wont need to worry about fixing to the top plate.

    But if you are going for smaller timber weatherboards, depending on the size you are choosing, it may just fix to the brickwork, then straight into the blocking.
    What type and size of cladding are you using. ?

  15. #15
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    FC Cladding.
    JH scyon stria 325mm or BGC stratum 300mm

    JH stria dont have starter strips (although their other FC cladding products do). it hangs about 25mm below the top course of brick, and gets nailed about 15mm above the plate...

    BGC stratum does have a starter strip, but its only about 30mm in height and gets nailed into the plate...

  16. #16
    Old Chippy 6K
    Join Date
    Mar 2007
    Location
    Canberra
    Age
    71
    Posts
    6,582

    Default

    From what I see in the pics and the OP's comments this is and will remain a non-compliant structure - and so should not get approved. Fiddling around won't change that.
    Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.

  17. #17
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by Bloss View Post
    From what I see in the pics and the OP's comments this is and will remain a non-compliant structure - and so should not get approved. Fiddling around won't change that.
    what? dont scare me... why not??

  18. #18
    Je pense, donc METRIX's Avatar
    Join Date
    Apr 2012
    Location
    Sydney North
    Posts
    9,697

    Default

    What did you spot in the pics Bloss ?

    Actually I have a question, was there originally double skin brick on this place, and has it been removed ?
    I am wondering why there is all new brickwork to the outer skin ?

  19. #19
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by METRIX View Post
    What did you spot in the pics Bloss ?

    Actually I have a question, was there originally double skin brick on this place, and has it been removed ?
    I am wondering why there is all new brickwork to the outer skin ?
    yeah originally double brick.. you can see the old brick is the solid smooth finish (dont know the technical name) brick, and the new brick is scratch face...
    i have bricked in some old windows, doors, extended some walls for the extension, and bricked 3 courses around the existing house to bring the external skin up to the height of the internal skin.

  20. #20
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Maybe that window having a lintel that can support a second storey!!! And new brickwork tied to old! These might be but 2 issues.
    Quote Originally Posted by METRIX View Post
    What did you spot in the pics Bloss ?

  21. #21
    1K Club Member paddyjoy's Avatar
    Join Date
    Sep 2011
    Location
    Sydney
    Posts
    1,577

    Default

    We need to get a petition going and get Allan Staines to write a book on second story additions/extensions. From a novice perspective they seem so much more complicated than building a house from scratch.

  22. #22
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by phild01 View Post
    Maybe that window having a lintel that can support a second storey!!!
    cant tell if that was sarcasm.....

  23. #23
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    No sarcasm intended. Second look at pics has me asking same question.
    Quote Originally Posted by melton2 View Post
    cant tell if that was sarcasm.....

  24. #24
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by phild01 View Post
    No sarcasm intended. Second look at pics has me asking same question.
    what part of them exactly?

  25. #25
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Quote Originally Posted by melton2 View Post
    what part of them exactly?
    Ok, Bloss indicated that by looking at pics, the structure should not get approval. So I looked at the pictures and noticed the window. The original house would only incorporate a lintel to support roof loads. Placing extra load on the lintel by way of a second story structure may lead to failure. I see a windows in all pictures. The other concern is the extent of the new brickwork and how it is tied back to the inner skin of brickwork. It is normal building practice that both skins be tied.

  26. #26
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by phild01 View Post
    Ok, Bloss indicated that by looking at pics, the structure should not get approval. So I looked at the pictures and noticed the window. The original house would only incorporate a lintel to support roof loads. Placing extra load on the lintel by way of a second story structure may lead to failure. I see a windows in all pictures. The other concern is the extent of the new brickwork and how it is tied back to the inner skin of brickwork. It is normal building practice that both skins be tied.
    all lintels (internal and external) have been changed to accommodate the 2nd story. you can see the original red lintel on the 2nd pic which is yet to be changed as that opening will be a door.. the new ones are galvanised.

    the new brickwork is tied into the internal skin by brick wall ties...

  27. #27
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Ok, can't offer much more, maybe ask Bloss why he says what he said.

    Quote Originally Posted by melton2 View Post
    all lintels (internal and external) have been changed to accommodate the 2nd story. you can see the original red lintel on the 2nd pic which is yet to be changed as that opening will be a door.. the new ones are galvanised.

    the new brickwork is tied into the internal skin by brick wall ties...

  28. #28
    Je pense, donc METRIX's Avatar
    Join Date
    Apr 2012
    Location
    Sydney North
    Posts
    9,697

    Default

    Quote Originally Posted by phild01 View Post
    Ok, Bloss indicated that by looking at pics, the structure should not get approval. So I looked at the pictures and noticed the window. The original house would only incorporate a lintel to support roof loads. Placing extra load on the lintel by way of a second story structure may lead to failure. I see a windows in all pictures. The other concern is the extent of the new brickwork and how it is tied back to the inner skin of brickwork. It is normal building practice that both skins be tied.
    We do a few 2nd story additions, and we deffinetly don't go around replacing lintels unless the engineer has stipulated this, it's usually just the larger openings they want beefed up, unless there is a partucular window in the way of a structural element, but the architects will usually design around the openings so they generally don't tend to pose any major problems.

    If it was masonry going on top then yes I agree these would pose a risk, but when its lightweight construction there is probably enough in them to be ok, but this all comes down to what the engineer has recommended fot the given situation.

  29. #29
    4K Club Member
    Join Date
    Nov 2008
    Location
    nsw
    Posts
    4,227

    Default

    It will be non compliant because of the plate & load being on the external wall, but an engineer could certify that method if you were desperate to go that way.
    regards inter

  30. #30
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Quote Originally Posted by melton2 View Post
    the new brickwork is tied into the internal skin by brick wall ties...
    Just interested, I had need recently to tie some existing brickwork to a stud frame. I devised a way to do this but I did wonder if there was a standard way or how others do it. Can you share how you secured the brick ties to your existing brickwork?

  31. #31
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by phild01 View Post
    Just interested, I had need recently to tie some existing brickwork to a stud frame. I devised a way to do this but I did wonder if there was a standard way or how others do it. Can you share how you secured the brick ties to your existing brickwork?
    no real standard way.
    some people cut out a channel, re mortar the channel, and then slide the wall tie in and stuff some more mortar in..

    i screwed 'L' shaped wall ties to the existing wall using masonry screws on opposite angles. just make sure the bend is very close to the screw, so if the tie gets pulled on, there is no slack..

  32. #32
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Very similar to what I did.
    Quote Originally Posted by melton2 View Post
    i screwed 'L' shaped wall ties to the existing wall using masonry screws on opposite angles. just make sure the bend is very close to the screw, so if the tie gets pulled on, there is no slack..

  33. #33
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by intertd6 View Post
    It will be non compliant because of the plate & load being on the external wall, but an engineer could certify that method if you were desperate to go that way.
    regards inter
    im going to pack the internal walls.. u and metrix gave me valid reasons for that..

    r u saying i should remove all load all together from the external wall? i was going to leave the external plates on to nail the cladding to.

    would it be better if i suspend that plate 10mm above the brickwork? i still need something for the first row of cladding to nail on to...

  34. #34
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    I go with what Metrix said "You would need to block out the ends of the joists anyway". Particularly if the joists are deep.

    Read more: http://www.renovateforum.com/f76/2nd...#ixzz2RnvpEdtu


    Quote Originally Posted by melton2 View Post
    im going to pack the internal walls.. u and metrix gave me valid reasons for that..

    r u saying i should remove all load all together from the external wall? i was going to leave the external plates on to nail the cladding to.

    would it be better if i suspend that plate 10mm above the brickwork? i still need something for the first row of cladding to nail on to...

  35. #35
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by phild01 View Post
    I go with what Metrix said "You would need to block out the ends of the joists anyway". Particularly if the joists are deep.

    Read more: http://www.renovateforum.com/f76/2nd...#ixzz2RnvpEdtu
    blocking ends is normal practice. i understand the need for it (i.e vertical and horizontal support during load and construction..).... but they are still going to be ~70mm off the brickwork...

    p.s the link you gave is to this thread...

  36. #36
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    What comes to mind is to have a colourbond profile milled to your design. Have it flash over the brick and profile it to be a starter course for the cladding. It seems you only need about 100mm for this and you won't need the plate. Maybe extend some blocking below joist level and screw the flashing to that. Just a quick thought I have.
    Sorry, don't know how that link 'snuck' in there!

    Quote Originally Posted by melton2 View Post
    blocking ends is normal practice. i understand the need for it (i.e vertical and horizontal support during load and construction..).... but they are still going to be ~70mm off the brickwork...

    p.s the link you gave is to this thread...

  37. #37
    4K Club Member
    Join Date
    Nov 2008
    Location
    nsw
    Posts
    4,227

    Default

    Quote Originally Posted by melton2 View Post
    im going to pack the internal walls.. u and metrix gave me valid reasons for that..

    r u saying i should remove all load all together from the external wall? i was going to leave the external plates on to nail the cladding to.

    would it be better if i suspend that plate 10mm above the brickwork? i still need something for the first row of cladding to nail on to...
    Thats correct, no load on outer skin, you need to suspend the plate or batten by at least 10mm so it doesn't touch outer skin, this reduces any problems from timber shrinkage of the wall plates & separates the outer skin from the timber to prevent rot.
    regards inter

  38. #38
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,579

    Default

    Agree as well, no contact with brick but it might be tedious securely nailing the plate to the underside of the joists with the brickwork in the way, why I suggested dropping the blocking down (being 50mm oversized). If the flashing idea is no good then instead of nailing bottom of cladding , then attach it to the dropped blocking with screws.

    Quote Originally Posted by intertd6 View Post
    Thats correct, no load on outer skin, you need to suspend the plate or batten by at least 10mm so it doesn't touch outer skin, this reduces any problems from timber shrinkage of the wall plates & separates the outer skin from the timber to prevent rot.
    regards inter

  39. #39
    Senior Member
    Join Date
    Apr 2012
    Location
    sydney
    Posts
    214

    Default

    Quote Originally Posted by phild01 View Post
    Agree as well, no contact with brick but it might be tedious securely nailing the plate to the underside of the joists with the brickwork in the way, why I suggested dropping the blocking down (being 50mm oversized). If the flashing idea is no good then instead of nailing bottom of cladding , then attach it to the dropped blocking with screws.
    skewed nails from the joists to the plate will do it...

    thanks everyone for their help....

  40. #40
    1K Club Member autogenous's Avatar
    Join Date
    Feb 2008
    Location
    Perth, WA.
    Posts
    1,219

    Default

    Its going to depend on your footing detail but still best floor joists should be bearing on both plates in this case.

    Does plate sit on flashing for a single story? no

    It was standard for plate to sit on the outside wall in the past. Its only eaves details that changed plates to internal walls.

    At the end of the day there should be a section detail of everything. Its about time Australia had nationalised CAD standards.
    https://www.instagram.com/perth_bricklayer_wa

  41. #41
    4K Club Member
    Join Date
    Nov 2008
    Location
    nsw
    Posts
    4,227

    Default

    Quote Originally Posted by autogenous View Post

    It was standard for plate to sit on the outside wall in the past. Its only eaves details that changed plates to internal walls.
    .
    Yes back in the good old days when there were no building regulations or standards, alas those days are gone, that's why building like that is not applicable these days.
    regards inter


Similar Threads

  1. Damp double brick wall
    By unexpert in forum Brickwork
    Replies: 17
    Last Post: 14th Aug 2012, 08:42 PM
  2. Re-use internal brick wall bricks on external wall
    By prof_montoya in forum Brickwork
    Replies: 4
    Last Post: 27th Sep 2011, 04:02 PM
  3. Plasterboard to damp brick wall
    By Frank111 in forum Plastering
    Replies: 4
    Last Post: 23rd Sep 2011, 06:54 PM
  4. Damp brick wall in garage?
    By JWC in forum Brickwork
    Replies: 1
    Last Post: 1st Aug 2010, 02:48 PM
  5. fixing timber door frame to external double brick wall
    By gmcginty in forum Doors, Windows, Architraves & Skirts
    Replies: 2
    Last Post: 5th May 2006, 11:06 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •