<PAGE>
 

                                                                Exhibit 10.1




April 26, 1999

Mr. David Ledecky
5305 Elliott Road
Bethesda, MD 20816

Dear Mr. Ledecky:

This termination agreement and release ("Termination Agreement") confirms the 
termination without cause of your status as a director, officer and employee of 
and with Building One Services Corporation (the "Company"), and each of the 
Company's direct and indirect subsidiaries, as of May 1, 1999 (the "Termination 
Date") due to the re-location and re-organization of the Company's corporate 
offices and the accompanying elimination of the position of Executive 
Vice-President and Chief Administrative Officer pursuant to the "Corporate 
Vision" presentation made to the Company's Board of Directors by the Company's 
President and Chief Executive Officer, Joseph M. Ivey, on February 25, 1999. In 
addition, for good and valuable consideration, the receipt of which is hereby 
acknowledged, the parties hereto mutually agree as follows:

1. Termination of Employment Agreement; Resignation as Employee, Officer and 
   -------------------------------------------------------------------------
Director. Your execution of this Termination Agreement hereby confirms in 
--------
writing the termination of your status as an employee and officer of the Company
and any and all of its subsidiaries, and your resignation from the Board of 
Directors of the Company and any and all of its subsidiaries, effective as of 
the Termination Date. Such execution further confirms that, except as otherwise 
provided herein, the Employment Agreement dated as of November 25, 1997 between 
you and the Company (the "Employment Agreement") is terminated effective May 1, 
1999, and all provisions thereof shall be null and void as of such date.

2. Payments and Benefits. In connection with your termination and resignation, 
   ---------------------
you shall receive the following (subject, in each case, to (i) your compliance 
with the terms of this Termination Agreement, and (ii) applicable statutory 
deductions and withholdings):

        (a) payment in an amount equal to the difference between $2,250,000 and 
the gross proceeds received by you as a result of your participation in the 
Company's tender offer (for example, if 250,000 of your stock options are 
retired in accordance with the Company's tender offer and you receive gross 
proceeds equal to $625,000, the amount due under this


<PAGE>
 
provision shall be equal to $1,625,000.) Such amount shall be paid whether or 
not the Company's tender offer is consummated;

        (b) continued coverage under the Company's group medical, dental, life 
insurance, short-term disability and long-term disability plans (the "benefits 
plans") for a period of one year following the Termination Date or until the 
date such coverages are obtained by you through another employer; provided, 
however, that for purposes of determining any period of "COBRA" coverage 
thereafter, your "qualifying event" shall be deemed to have occurred on the 
Termination Date, and provided that in the event the Company amends any or all 
of its benefits plans during the one-year period, that you shall receive 
coverage that is at least equivalent in scope to your current coverage; and

        (c) your employee contributions and any vested employer contributions 
accrued under the Company's 401(k) plan in accordance with the terms thereof.

The parties agree that the payment set forth in Section 2(a) is for cancellation
of the Employment Agreement and your agreements, releases, and waivers set forth
herein, and not remuneration for services rendered, and that therefore the 
payment shall not be subject to federal employment tax withholding. You agree, 
however, that you shall reimburse the Company for any amount it may be required 
to pay in respect of such failure to withhold to the extent such amount 
represents taxes and interest for which you would otherwise be responsible 
(including your share of FICA taxes).

The parties further agree that $1,200,00 of the payment set forth in Section 
2(a) shall be made no later than April 30, 1999. The remainder of the payment 
set forth in Section 2(a) shall be made on the earlier of (i) six business days 
following consummation of the company's tender offer and (ii) May 14, 1999.

3. Cessation of all Compensation and Benefits; Stock Options.
   ---------------------------------------------------------

        (a) From and after the Termination Date, and except as otherwise 
expressly set forth in this Termination Agreement, you will not receive payments
or benefits of any kind from the Company or its subsidiaries, and you expressly 
acknowledge and agree that, except with respect to the payments and benefits 
specifically set forth in this Termination Agreement, you are not entitled to 
any payment or benefit whatsoever.

        (b) The stock options granted to you by the Company in November, 1997 
pursuant to Section 3(g) of the Employment Agreement (which you acknowledge are 
the only stock options granted to you by the Company) shall be exercisable only 
in connection with the Company's current tender offer (the "Company's tender 
offer"). Pursuant to the Company's request, you hereby agree to tender your 
stock options to the maximum extent permitted under the Company's tender offer. 
Notwithstanding the relevant provisions of Section 5(d) of the Employment 
Agreement regarding the immediate vesting and exercisability of your stock 
options upon a termination without cause, you and the Company hereby agree that 
those stock options granted to you by the Company that are not accepted under 
the Company's tender offer


<PAGE>
 
shall expire in their entirety on the date full and final payment is made to you
by the Company pursuant to Sections 2(a) above of this Termination Agreement.

4. Payment is in Consideration of Release and Other Continuing Obligations. You 
   -----------------------------------------------------------------------
understand and agree that the payments provided for in Section 2 of this 
Termination Agreement are being provided to you in consideration for your 
acceptance and execution of, and in reliance upon your agreements in, this 
Termination Agreement, including but not limited to the release contained 
herein.

5. Return of Documents and Property. You shall forthwith return and deliver to 
   --------------------------------
the Company (a) any and all original and duplicate copies of all files, 
calendars, books, records, notes, manuals, computer disks, diskettes and any 
other magnetic and other media materials you have in your possession or under 
your control belonging to the Company or its subsidiaries and (b) any and all 
original and duplicate documents, materials and other property (including, 
without limitation, computer files) containing trade secrets or other 
Confidential Information (as defined below) relating to the business and affairs
of the Company or its subsidiaries, or other confidential or proprietary 
information concerning the Company or its subsidiaries and/or their customers or
operations, including but not limited to information regarding any investments 
of the Company or its subsidiaries. You hereby represent and warrant that you 
have returned all Company keys, credit cards, office equipment (including 
cellular telephones and computer equipment) and other property belonging to the 
Company or any of its subsidiaries to the Company.

6. Nondisclosure of Confidential Information. You agree that you will not at any
   -----------------------------------------
time disclose or use, or authorize any other person or entity to publish, 
disclose or use, any secret or Confidential Information of or about the Company 
or its subsidiaries. For purposes hereof, the term "Confidential Information" 
shall include, by way of example and without limitation, matters of a technical 
nature, "know-how," formulas, secret processes, works of authorship, computer 
programs (including documentation of such programs), services, materials, patent
applications, new product plans, other plans, technical information, technical 
improvements, test data, progress reports and research projects, and matters of 
a business nature, such as business plans, prospects, financial information, 
marketing plans and strategies, proprietary information about costs, profits, 
markets, sales, prices, lists of customers and suppliers of the Company and its 
subsidiaries, procurement and promotional information, credit and financial data
concerning customers or suppliers of the Company and its subsidiaries, 
information relating to the management, operation and planning of the Company 
and its subsidiaries, and other information of a similar nature to the extent 
not available to the public, and plans for future development.

7. Confidentiality of this Agreement. You and the Company agree that unless a 
   ---------------------------------
mutual waiver of this provision is agreed upon by the parties, the terms of this
Agreement shall remain confidential except to the extent that disclosure of any 
of the terms of the Agreement are required to be disclosed by law or to any 
legal and accounting representative, or other agent or representative, of the 
respective parties. The Company agrees that you shall have the right to advance 
review, and to make reasonable comments upon, any proposed public disclosure by 
the Company regarding any or all terms of this Termination Agreement.

8. Non-Disparagement. You agree that you will not, directly or indirectly, 
   -----------------
disparage (whether in writing or orally) the Company or the Releasees (as 
defined below) in any manner whatsoever at

                                       3


<PAGE>
 

any time with respect to the Company's operations and the Releasees' respective 
roles in the Company's operations. The Company mutually agrees that it will not,
directly or indirectly, disparage (whether in writing or orally) you in any 
manner whatsoever at any time with respect to your employment at the Company, 
your role as an officer and director of the Company, and the termination of your
status as an employee, officer and director of the Company.

9. Releases
   --------

        (a) You hereby agree to accept the payment and benefits provided for in 
Section 2 hereof in full resolution and satisfaction of, and hereby IRREVOCABLY 
AND UNCONDITIONALLY RELEASE, REMISE AND FOREVER DISCHARGE the Company, its past,
present and future direct and indirect parents, subsidiaries, affiliates, 
divisions, predecessors, successors, and assigns, and their respective current 
and former officers, directors, shareholders, representatives, agents and 
employees, in their official and individual capacities, jointly and individually
(the "Releasees") from, any and all agreements, promises, liabilities, claims 
and demands of any kind whatsoever, in law or equity, whether known or unknown, 
suspected or unsuspected, fixed or contingent, apparent or concealed, which you,
your respective heirs, executors, administrators, successors or assigns ever 
had, now have or in the future may have, including any and all claims relating 
in any way to the Company, your ownership interest therein, or arising out of or
relating to your employment, the Employment Agreement, Stock Option Grant 
Certificate, your compensation and benefits with the Company and/or the 
termination thereof, and any and all contract, tort or fraud claims, claims for
defamation or other personal injury, claims under any federal, state or 
municipal wage payment, discrimination or fair employment practices law, statute
or regulation and claims for costs, expenses and attorneys' fees with respect 
thereto, arising from the beginning of the world through the effective date of 
this Letter Agreement, in each case, against the Company or any of the 
Releasees, other than any claims with respect to the Company's breach of this 
Termination Agreement. However, it is agreed that you do not waive your rights 
for coverage or indemnification under any directors & officers policy, or 
pursuant to the Articles of Incorporation or bylaws of the Company for acts or 
omissions occurring during your employment. Furthermore, the Indemnity Agreement
dated November 25, 1997 made by and between you and the Company shall survive 
this Termination Agreement and remain in full force and effect. The Company also
hereby agrees to provide you, your executors, heirs, administrators and legal 
representatives, with specific, additional, full and complete indemnification 
with respect to any legal claims that may arise from or respecting this 
Termination Agreement and the maximum tender of your stock options as 
contemplated and agreed to in Paragraph 3(b) hereof. The indemnification 
provided shall be the same in form and substance, and in addition to, the 
indemnification provided in the Indemnity Agreement dated November 25, 1997 made
by and between you and the Company.

        (b) By signing this Termination Agreement and by acceptance of the 
payment and benefits provided for in Section 2 above, you hereby WAIVE, RELEASE 
AND COVENANT NOT TO SUE the Company or the Releasees with respect to any matter 
relating to or arising out of any claims being released hereunder, and you agree
that you will not (i) file, charge, claim, sue or cause or permit to be filed 
any civil action, suit or legal proceeding for any claims which are being 
released hereunder against the Company or the Releasees, whether in the form of 
a federal, state or municipal court lawsuit or administrative agency action, an 
arbitration proceeding or otherwise, (ii) seek reinstatement or any other 
monetary, equitable or personal relief of any kind from the Company or the 
Releasees, however that relief might be called, on the

                                       4

<PAGE>
 

basis of any such claim, or (iii) accept any such relief (as described in 
subclause (ii) above) on the basis of any claims which are being released 
hereunder if sought by any person, organization or other entity other than you 
or acting for you or on your behalf. You represent and warrant as of the date 
hereof (i) that you have not filed any claim or demand for relief against the 
Company or Releasees, (ii) that there are no outstanding claims, or other claims
or demands for relief within the meaning of this Section 9 and (iii) that there 
has been no assignment of any such claims.

        (c) By signing this Termination Agreement and in consideration for the 
releases granted by you in Sections 9(a) and 9(b) above, the Company, its past, 
present and future direct and indirect parents, subsidiaries, affiliates, 
divisions, representatives, agents, predecessors, successors, and assigns, 
jointly and individually, hereby IRREVOCABLY AND UNCONDITIONALLY WAIVE, RELEASE,
REMISE, FOREVER DISCHARGE AND COVENANT NOT TO SUE you, your executors, heirs, 
administrators, and legal representatives with respect to any and all claims and
demands of any kind whatsoever, in law or equity, whether known or unknown, 
suspected or unsuspected, fixed or contingent, apparent or concealed, arising 
out of or related to your Employment Agreement and your status and role as an 
employee, officer, director, agent, trustee, or representative of the Company 
and its past, present and future direct and indirect parents, subsidiaries, 
affiliates, divisions, predecessors, successors and assigns, arising from the 
beginning of the world through the effective date of this Termination Agreement,
other than any claims with respect to your breach of this Termination Agreement.
The Company further agrees that it will not (i) file, charge, claim, sue, or 
cause or permit to be filed any civil action, suit or legal proceeding for any 
claims which are being released hereunder against you, whether in the form of a 
federal, state or municipal court lawsuit or administrative agency action, an 
arbitration proceeding or otherwise, (ii) seek reinstatement or any other 
monetary, equitable or personal release of any kind from you, however that 
relief might be called, on the basis of any such claim, or (iii) accept any such
relief (as described in subclause (ii) above) on the basis of any claims which 
are being released hereunder if sought by any person, organization or other 
entity other than the Company, acting for the Company or on its behalf. The 
Company represents and warrants that as of the date hereof (i) it has not filed 
any claim or demand for relief against you, (ii) that there are no outstanding 
claims or demands for relief within the meaning of this Section 9(c) and (iii) 
that there has been no assignment of any such claims.

10. No Admission. Nothing contained in this Termination Agreement shall be 
    ------------
deemed to constitute an admission or evidence of any wrongdoing or liability on 
the part of you or the Company or the Releasees.

11. Future Cooperation. You further agree that upon the Company's reasonable 
    ------------------
request you will use reasonable efforts to assist and cooperate with the Company
and the Releasees in connection with the defense or prosecution of any claim 
that may be made against or by the Company or the Releasees, or in connection 
with any ongoing or future investigation or dispute or claim of any kind 
involving the Company or the Releasees, including any proceeding before any 
arbitral, administrative, regulatory, self-regulatory, judicial, legislative, or
other body or agency. In the event of the cooperation as contemplated by this 
Section 11, the Company shall reimburse you for all of your reasonable costs and
expenses incurred by you in providing such cooperation. The Company also agrees 
to reimburse you at a mutually agreed upon rate for any work the Company

                                       5


<PAGE>
 

requests your cooperation in completing (and which you are able to and mutually 
agree to perform) following the execution of this Agreement.

12. Successors and Assigns. This Termination Agreement shall inure to the 
    ----------------------
benefit of and shall be binding upon the parties hereto and their respective 
successors and assigns, including but not limited to (i) with respect to the 
Company, any entity with which the Company may merge or consolidate or to which 
the Company may sell substantially all of its assets, and (ii) with respect to 
you, your executors, administrators, heirs and legal representatives.

13. Severability; Headings. In the event that any provision of this Termination 
    ----------------------
Agreement shall be held by a court of proper jurisdiction to be invalid, void or
voidable or otherwise unenforceable, the balance of this Letter Agreement shall 
continue in full force and effect unless such construction would clearly be 
contrary to the intentions of the parties or would result in an unconscionable 
injustice. The headings of the sections and paragraphs of this Letter Agreement 
are for convenience of reference only and shall not constitute a part hereof.

14. Miscellaneous: Choice of Law. This Termination Agreement may be executed in 
    ----------------------------
several counterparts, each of which shall be deemed to be an original but all of
which together will constitute one and the same instrument. This Termination 
Agreement constitutes the entire agreement, and supersedes all prior agreements,
of the parties hereto relating to the subject matter hereof, and there are no 
written or oral terms or representations made by either party other than those 
contained herein and therein. This Termination Agreement cannot be modified, 
altered or amended except by a writing signed by all the parties. No waiver by 
either party of any provision or condition of this Termination Agreement at any 
time shall be deemed a waiver of such provision or condition at any prior or 
subsequent time or of any provision or condition at the same or any prior or 
subsequent time. This Termination Agreement shall be governed by and construed 
in accordance with the domestic laws of the State of Delaware, without giving 
effect to any choice of law or conflict or law provision or rule (whether of the
State of Delaware or any other jurisdiction) that would cause the application of
the laws of any jurisdiction other than the State of Delaware.

15. Facsimile Signatures Valid. Execution of this Termination Agreement with 
    --------------------------
signatures transmitted via facsimile shall be considered valid.

                                  *  *  *  *

If this Termination Agreement conforms to your understanding and is acceptable 
to you, please indicate your agreement by signing and dating the enclosed copy 
of this Termination Agreement where indicated and returning it to the Company no
later than April 27, 1999.



Sincerely,

Building One Services Corporation

                                       6


<PAGE>
 

By: _____________________________
    Name:
    Title:

THIS TERMINATION AGREEMENT IS A LEGAL DOCUMENT. YOU SHOULD CONSULT WITH AN 
ATTORNEY PRIOR TO SIGNING THIS TERMINATION AGREEMENT.

BY SIGNING THIS TERMINATION AGREEMENT YOU ACKNOWLEDGE THAT YOU ARE COMPETENT, 
THAT YOU ARE COMPETENT, THAT YOU HAVE BEEN PROVIDED WITH THE OPPORTUNITY TO 
REVIEW AND CONSIDER THIS TERMINATION AGREEMENT WITH AN ATTORNEY OF YOUR CHOICE 
AND YOU HAVE USED SUCH REVIEW PERIOD TO THE EXTENT YOU DESIRED, THAT YOU HAVE 
READ AND UNDERSTAND AND VOLUNTARILY ACCEPT THIS TERMINATION AGREEMENT AS FULLY 
AND FINALLY RESOLVING, WAIVING AND RELEASING ANY AND ALL CLAIMS WHICH YOU MAY 
HAVE AGAINST THE COMPANY AND RELEASEES (AS DEFINED HEREIN), THAT NO PROMISES OR 
INDUCEMENTS HAVE BEEN MADE TO YOU EXCEPT AS SET FORTH IN THIS TERMINATION 
AGREEMENT, AND THAT YOU HAVE SIGNED THIS TERMINATION AGREEMENT FREELY AND 
VOLUNTARILY, INTENDING TO BE LEGALLY BOUND BY ITS TERMS. THE FOREGOING IS A 
SUMMARY DESCRIPTION OF THE GENERAL IMPORT OF THIS INSTRUMENT AND DOES NOT ALTER 
OR AMEND THE DETAILED PROVISIONS CONTAINED IN THE BODY HEREOF.

ACCEPTED AND AGREED:




_______________________________                         Date: _________________
David Ledecky


                                       7