I am a general contractor and I will be renovating a 19th century farmhouse that I just bought in Central VA. It is set on piers about 14″ off the ground and two sill beams need to be replaced (the two beams on the inside faces of an L-shaped layout Quick diagram= L <- ) . The joists are in surprisingly great condition considering the mush that the sills turned into.
Questions
Can I jack up the house to replace two beams at a time or should I concentrate on one at a time?
Does the framing of the house dictate how I go about this? Does baloon framing require a different approach? I haven’t opened any walls yet so I do not know what I have
What material should I use for the replacement beams. Is pressure treated the best for this?
Any help would be greatly appreciated
Replies
replace two beams at a time
as a practical matter, you'll be doing one at a time, but I do understand your question -
has the house sagged signifigantly? if you need to raise the structure more than a inch or two, better treat it as one larger project and work all 'at the same time' -
if the structure is timber framed, which seems possible, the redundancy of the frame keeps the structure square and you may find that there are 2 or 3 points (posts) bearing the weight of that side of the house - I'd suggest careful analysis of situation -
you might consider rerplacing the beams with new/used beams of similar dimension - timber framed barns often set on white oak or walnut which are rot resistant - there is a market in salvaged material of this sort, or check around the neighborhood for declining barns -
DOUD - semi-pro barn jacker
ya i agree with doud the first thing is to see if it is sagged at all. if you are just replacing a mush beam but the rest of structure is still at grade you only need just enough clearance to install new piece and the less you move it the better. if you have to move the structure do it gradually, the reverse of the sagging process, it didn't all sag in one day. i like to use heavy duty trench shoring screw jacks for this and give em a half a turn a day or so untill it is at grade. this is a very dangerous procedure and have seen long pieces kick out under pressure. be carefull and keep it as short as possible. also you may consider locking the low point where it is and lowering rest of the structure to level. is it all low at the perimiter but high in the center. again this should be done slowly over time. the carefull analysis of the situation is a real good idea. also with balloon framed walls the joists will be attached to a ledger. is the floor level? a temporary support for the joists at a point close to the ledger that you can jack may be very helpfull. and if it is only on piers even on the outside perimiter i would install a foundation with a modified foundation bolt that is embedded in the concrete sticking up that you can use it after concrete is cured to raise, by screwing, to make fine adjustments over time. i have used this method with great success several times. it prevents the danger of screw jacks kicking out and you can even pour concrete between existing supports and after it is at final grade tie it all in with short pony walls and plywood sheer panels.
Hard to say without being there but I would probably jack it all at once.
If this is balloon framed, that is possibly an advantage to you. You can bolt a ledger to the wall at a higher location and jack to it so you have fewer jacks in your way at the base level while you replace the timbers. Use PT, fir, or white oak.At 14" off the ground, there should be enough ventilation to prevent rot so look for what is the source of the moisture that caused the rot. If the walls are leaking rain driven in by wind, then you have to adress that too.
Excellence is its own reward!
I used to tear down houses outside of Charlottesville, for recycling. Most of the late 19th century ones were balloon framed. A lot of the houses had a white oak beam running under the center of the floor, sitting directly on or real close to dirt. Most were still in great shape.
If the floor joists are attached to the wall framing, and just the sill is rotten, ledger would be the way to go.
The new sill should be pressure treated where it rests on the piers, but the rest could be any framing grade lumber.
And, addressing why she rotted in the first place should be top priority. Maybe water from the roof valley formed by the ell?
Good luck
EliphIno!
Are there any house movers in your area? I'd suggest paying one of them a consulting fee to look at the job in person and advise you. I did a little of this a while ago, it's in the photo section of this site under "New footing in the middle of the house". From that experience I'd suggest two things:
Use lots of cribbing and shims.
Pull the baseboards in the affected area and rake out the bottom of the plaster to about 1/2" above the sole plates. That'll minimize the transfer of stresses to the plaster as the structure moves.
-- J.S.
I have worked on two house moving jobs and found that they hold together remarkably well. I would consult a house moving company.
One thing that I didn't see the other posters mention is that you should try to do the jacking very slowly. Moving very gradually you can get away with a lot of movement that would otherwise cause damage. I would attempt to move the whole area up at once because the less up and down and warp around, the better your chances of keeping it sound. At least, that's what I've found.