replacing a sill plate. is it as easy as it looks?

[robgil]

its around 6 foot long , on a gable end and has three studs ontop. two of the studs may need a new piece scarfed in and the third is dubious. the brick plinth is also rubbished and may need rebuilding with new bricks.
so , from what i can see is i need to acro up the ceiling with acros and scaffold boards (the joists run towards the sill plate rather than parallel to it and rest on a wall plate) , then remove the plinth carefully , drop down the sill plate after drilling and removing any pegs on the mortise joints , cut the studs up to the good wood taking away only the rotten stuff , measure the off cuts and make up new bits to scarf (butt joint with steel support brackets either side?) in then mortice and tennon into the new sill plate , then using car jacks jack the new plate with studs in place up to where is should be then build the plinth back up underneath it.

surely it cannot be that easy , can it? how do i stop the wall plate from dropping down or would the acros support this as well as the ceiling?

 

[Jon Maine]

Depends on how the joists are connected to the wall, I rather suspect you may be better using a strong boy on an acrow prop or even more than one picking up the frame ( horizonzal member) of the wall directly above the failure otherwise yes it should be as simple as you describe, use some good joints though.

Have a look at http://www.bmulfordhistoriccarpentry.co.uk/Conservation.html

 

[robgil]

waw , i am hoping my frame isn't that bad , ive just seen two sole plates so far that need work/replacing and one that needs a repair but I have yet to look at the loft space and behind the cement render on one gable end , I do think I have got off lightly though considering how much worse it could easily have been.

i think the joists are resting ontop of the wall plate but you are right , i will still need to support it anyway. another worry is the stud in the corner of the room , i am not sure what it rests on so i need to investigate this further.
i am not experienced in scarfing and i fear a complicated scarf joint will show my inexperience and look botched and unprofessional , i may have trouble pulling off a scissor scarf for instance but a half lap scarf i might be ok with.

a strong boy is a good idea (i had to look it up , never seen or heard of one before) , thank you.

 

[Jon Maine]

waw , i am hoping my frame isn't that bad , ive just seen two sole plates so far that need work/replacing and one that needs a repair but I have yet to look at the loft space and behind the cement render on one gable end , I do think I have got off lightly though considering how much worse it could easily have been.

i think the joists are resting ontop of the wall plate but you are right , i will still need to support it anyway. another worry is the stud in the corner of the room , i am not sure what it rests on so i need to investigate this further.
i am not experienced in scarfing and i fear a complicated scarf joint will show my inexperience and look botched and unprofessional , i may have trouble pulling off a scissor scarf for instance but a half lap scarf i might be ok with.

a strong boy is a good idea (i had to look it up , never seen or heard of one before) , thank you.

if the floor joists are only rested on the wallplate and you support the floor joists the floor may stay in place but the wall drop. Just double check and consider before you do anything or you could end up with a complete wall dropped several inches.

Half lap should be fine for what you require. Dont forget to use stainless bolts/ threaded bar due to the corrosive nature of tanic acid in the oak.

 

[robgil]

will do , thank you for the advice , its greatly appreciated.
i shall update this thread to let you know how i get on when i start the work on the sill.

 

[JoceAndChris]

a strong boy is a good idea (i had to look it up , never seen or heard of one before)

Just look in the mirror!

I remain beyong impressed at all the major work you're taking on. Good luck!

 

[Penners]

Half lap should be fine for what you require. Dont forget to use stainless bolts/ threaded bar due to the corrosive nature of tanic acid in the oak.

I agree with Jon about the scarfing joint (who would I be to disagree??). The following diagrams may be of help - have a look at the very bottom one.

http://tinyurl.com/yf8jada

The important thing is to ensure that the two half-lap rebates are exactly the same length, so that each crosscut face is taking its equal share of the load.

 

[Flyfisher]

Middi can certainly make replacing a sill plate look easy! Have you looked at his website or seen his 'Restored To Glory' programme on BBC?

 

[Jon Maine]

Middi can certainly make replacing a sill plate look easy! Have you looked at his website or seen his 'Restored To Glory' programme on BBC?

Yes Middi is an expert, someone told me he did his apprenticeship on the colosseum !!

Certainly look at his website or even talk to him on here he is someone who is a natural with this type of thing and knows his stuff.

 

[Penners]

Middi is an expert...talk to him on here

You'll have to catch him first! He's very occupato at the moment, so doesn't pop in very often.

 

[robgil]

cheers guys , does anyone have a link to his site?

 

[Jon Maine]

cheers guys , does anyone have a link to his site?

http://middideluca.co.uk/

not much info there tho' Middi, more pictures please of your wonderful work, many pages please.......

 

[robgil]

lovely , thanks. not much info there but i have no doubt he would be a good source of info and advice. it must be a wonderful job he has.
i have heard various opinions on putting lead in between the brick plinth and the plate , is this necessary? or would a bed of lime mortar be a better solution?

 

[middi]

Replacing rotten wall plates ( or part of it) is a relative simple operation on a timber framed wall. As , in your case, it is an end gable wall, the chances are that if you removed most of the lower studs without any support at all the intermediate tie beam above these studs will hold everything above. If this beam is quite sturdy and in good condition and supported at each end it should easily support quite a large open span. If unsure use DIY wood support, if S#@t scared use acro props.

Having repaired the wall plate and studs as you have indicated and supported by all those nice people on this site, build the wall below the replaced plate and use the same material ( lime mortar, soft bricks, stone and lime etc...) as existing , do not be tempted to use dpc or other dpc materials because you will transfere dampness in other parts of the unrepaired sections. If you repaired the whole wall plate there may be a case for using dpc if correctly done. If the external studs will be exposed on no account you shoud use any dpc under the wall plate.
Apart from a car jack to hold the repaired plate up whilst rebuilding the wall, you can use a 4x1 or 4x2 piece of wood screwed on the bottom plate and on the top beam ( if applicable) therefore trapping the repaired studs in position so that the car jack can be removed and life made much easier to rebuild wall . Use one piece of wood at each end of the repaired lower plate.

As to the Colosseum Jon, if I had built the place it would still be in use today, albeit less Christians roaming the streets :wink:
Peners is spot on, Yes I am very "occupato" these days hence spent little time on PPuk.
As to my Webb site one of the BBC computer wiz kids said it was a good idea if he built me a site. I have done nothing to it ever since.

 

[robgil]

great stuff , thanks. do i sit the plate directly on the brick or on mortar? probably not much need for a dpc as i tend to sort any damp through drainage. the floor is cement with a dpc but i plan to remove this and lay floor bricks , perhaps on a thin limecrete bed and sand?

this is the room , the rotten plate is right of the fireplace.

i am not sure what the corner stud is resting on and the top wall plate is covered in lime render so i cannot see what exactly is going on up there. i will investigate further on sunday when i am next up there.

 

[middi]

Great pics robgil, It looks very straight forward.

If you removed both stud walls from either side of the chimney breast nothing is likely to happen because the top beam is resting on the chimney and only 25 per cent of pressure from above on each corner, just make sure there is no masonary void under the corner posts and it should be fine. if you need to support the end of the top plate ( investigate this) all you really need is a 4x2 at a slight angle under the plate with an appropriate screw so that it does not slip.

 

[middi]

Forgot, use a bed of lime mortar under the beam to bed it on the bricks. This is a bit tricky as the plate cannot be lowered onto the mortar, I suggest you build the wall but leave a gap of at least 15mm between the bricks and the plate this gap will make it a lot easier to "squeeze" the bedding mortar under the plate with a small trowel.
Do not get any lime on the inner surface of the oak beams or studs, the tanic acid will react with this and you will end up with very unsightly marks for a few years ( only if they need to be exposed of course)

 

[robgil]

cheers midi , im not sure about masonry voids under the corner post , i do know that the plinth under the rotten plate has disintegrated badly and it seems to be rubble and sand more than brick although from the outside it looks fine (the outside is rendered from the brick plinth up) so i think when i am next up there on sunday i shall have a good poke around. i am putting this job off for a few weeks as i have other more important stuff to do like put in a bathroom to make the house habitable so that gives me plenty of time to prepare. it does seem quite straight forward enough though , i take it i should cut away some of the concrete floor first , should i dig down a bit to lay the bricks or put a bed of mortar in first or should i just rebuild it as it comes out?

 

[middi]

It appears that the cottage has been there for about 350/400 years therefore no concern about foundations for a couple of reasons
1) The ground is well consolidated over all those years ( hence the cottage still standing !!!)
2) It is not a " solid" masonary building where a slight "give" in the foundations will result in a massive crack in the walls.

If the original brick plinth lower bicks are still there and in reasonable condition just leave them alone and just replace the top 2 or three courses.
It must be remembered that the wall plate spreads the weight and is quite flexible like the rest of the building so there is little point in stiffening the foundation more than all the others already existing, you may introduce more problems by doing this.

 

[robgil]

no worries , thank you. i shall have a good probe around on sunday and report back.