Expert: Dave Johnson - 5/31/2009

Question
QUESTION: I want to extend my 1990 double wide manufactured home 5'
on each gable end. Of course the end walls are load bearing
supporting the roof. and there is the central beam that
runs lengthwise to bolt the two halves together. It comes
doen from the ceiling about 8". The ceiling is vaulted
following the roof's 3/12 pitch. I would prefer to not have
a sofit running from side to side, but can deal with
extending the longitudinal beam on the marriage wall
(indeed it would look funny if I didn't as it is 14" in
from one of the bedroom walls).  The master suite with an
ensuite bath (divided between the house halves) is on one
end and the two secondary bedrooms (one per house half)are
on the other end.
My questions are:
1. can this be done at all?
2. What will be needed to transfer the roof load?
3. How are the walls and floors of the extension tied into
the existing structure?
4. Before any work is done, I will be retrofitting an FHA
approved foundation under the existing home which will
still entail piers under the house in addition to the
perimeter foundation wall. How would I then handle the
foundation for the addition?
5. how do I locate a structural engineer with knowledge of
Hud code requirements to sign off on any plans.
I know this is a lot but am hoping for any information that
could help me plan out the total  remodel of my home.
Thank you for any info you can provide.

ANSWER: Hi Trilby,
First, the end walls:
In order for you to extend the center beam, it will have to be spliced
back away from where it ends now. Otherwise there would be a very weak spot where you remove the wall. I would suggest that you expose the existing beam, then either cut back the outer planks on either side at least 3 feet. Then add new ones to your 5' extension, filling in the
remaining planks, nailing or screwing well. Now you can frame to match the existing rafters. OR: if there is room, you could slide a 1/4" steel plate into the existing beam and through bolt both the existing and new beams.
The walls and floors will be framed just as they are now, simply nailing/screwing them to the existing.
The foundation can be done the same as it is now, but first drill some 1/2" holes into the old foundation, and cut pieces of 1/2" (#4)re-bar
about 12" long as dowels to tie the foundations together.
The local code enforcement officer should be able to assist you in
any engineering questions.

If this is not clear enough, please mail me again...best of luck!

Dave





---------- FOLLOW-UP ----------

QUESTION: Dave thank you so much for your answer. I've spent some
time researching this on the net and asked mobile home
experts on the net without any good results, so your time
is much appreciated and very helpful.

you wrote:In order for you to extend the center beam, it
will have to be spliced
back away from where it ends now. Otherwise there would be
a very weak spot where you remove the wall. I would suggest
that you expose the existing beam, then either cut back the
outer planks on either side at least 3 feet. Then add new
ones to your 5' extension, filling in the
remaining planks, nailing or screwing well.

I'm not picturing what you are describing. Do you mean
remove the decorative covering from the marriage beam
inside the house, then remove siding from the gable end and
possibly some roofing material as well to expose the beam?
I am thinking I would remove all the siding, exposing the
existing framing, build my foundation and flooring, frame
up extension's walls, then extend the beam and roof. Is
that right?
Again thank you so much. You've already been very helpful.
BTW can you give me a ball park figure for what I can
expect each extension to cost using a combination of
contractor work and sweat equity.
Trilby

Answer
Hi Again,
No, I meant to do just as you said, do all other framing and then extend the beam, by exposing it from the inside, there should be no need to remove any exterior material.
A figure for this  will vary from area to area. (labor rates, materials costs, # of windows added etc.)

If I were doing it here in Maine, I guess it would run about
$4,000 per end.
Dave