
2025 Rhif 704 (Cy. 119)
Adeiladu Ac Adeiladau, Cymru
Rheoliadau Adeiladu (Diwygio) (Cymru) 2025
Gwnaed 17 Mehefin 2025
Gosodwyd gerbron Senedd Cymru 19 Mehefin 2025
Yn dod i rym 20 Rhagfyr 2025

Mae Gweinidogion Cymru, drwy arfer y pwerau a roddir iddynt gan adran 1(1) o Ddeddf Adeiladu 1984, a pharagraffau 7, 8 a 10 o Atodlen 1 iddi, yn gwneud y Rheoliadau a ganlyn.

Mae Gweinidogion Cymru wedi ymgynghori â Phwyllgor Cynghori Cymru ar Reoliadau Adeiladu ac â’r personau eraill hynny y maent yn ystyried eu bod yn briodol yn unol ag adran 14(7) o Ddeddf Adeiladu 1984.
Enwi, dod i rym a chymhwyso
1 

(1) Enw’r Rheoliadau hyn yw Rheoliadau Adeiladu (Diwygio) (Cymru) 2025 a deuant i rym ar 20 Rhagfyr 2025.
(2) Mae’r Rheoliadau hyn yn gymwys o ran Cymru.
Diwygio Rheoliadau Adeiladu 2010
2 

(1) Mae Rheoliadau Adeiladu 2010 wedi eu diwygio fel a ganlyn.
(2) Yn rheoliad 2(6) (dehongli)—
(a) ar ddiwedd is-baragraff (a)(iv), hepgorer “and”;
(b) yn lle is-baragraff (b), rhodder—“
(b) “relevant metal composite material” means any panel or sheet, having a thickness of no more than 10mm, which is comprised of a number of layers—
(i) two or more of which are made of metal, alloy or metal compound; and
(ii) one or more of which is substantial and is made of a material having a gross calorific value of more than 35 MJ/kg when tested in accordance with BS EN ISO 1716:2018 entitled “Reaction to fire tests for products – Determination of the gross heat of combustion (calorific value)” (ISBN 978 0 580 93554 1) published by the British Standards Institution on 31st July 2018;
and for these purposes a substantial layer is one which is at least 1mm thick or has a mass per unit area of at least 1kg per m²;
(c) “specified attachment” means—
(i) a balcony attached to an external wall;
(ii) a solar shading device (excluding a solar shading device attached to the wall at a height of no more than 4.5 metres above ground level); or
(iii) a solar panel attached to an external wall; and
(d) “solar shading device” means a device attached to the external surface of an external wall for reducing heat gain within a building by shading or deflecting sunlight.”
(3) Yn rheoliad 6(1)(c) (gofynion yn ymwneud â newid defnydd sylweddol), yn lle “fifteen” rhodder “eleven”.
(4) Yn rheoliad 7 (deunyddiau a chrefftwaith)—
(a) ar ôl paragraff (1), mewnosoder—“
(1A) Building work must be carried out so that relevant metal composite material does not become part of an external wall, or specified attachment, of any building.”;
(b) ym mharagraff (3)—
(i) ar ôl is-baragraff (d), mewnosoder—“
(da) fibre optic cables;”;
(ii) yn is-baragraff (e), ar ôl “ground level”, mewnosoder “or up to 300mm above that level”;
(iii) ar ôl is-baragraff (h), mewnosoder—“
(ha) components associated with a solar shading device excluding components whose primary function is to provide shade or deflect sunlight such as the awning curtain or slats;”;
(iv) ar ddiwedd is-baragraff (i), hepgorer “or”;
(v) ar ddiwedd is-baragraff (j), mewnosoder—“; or
(k) materials which form the top horizontal floor layer of a balcony which are of European Classification A1fl or A2fl-s1 (classified in accordance with BS EN 13501-1:2018 entitled “Fire classification of construction products and building elements. Classification using test data from reaction to fire tests” (ISBN 978 0 580 95726 0) published by the British Standards Institution on 14th January 2019) provided that the entire layer has an imperforate substrate under it.”;
(c) ym mharagraff (4)(a)(iii), hepgorer “(excluding any room in a hostel, hotel or boarding house)”.
Darpariaethau trosiannol
3 

(1) Nid yw’r diwygiadau a wneir gan reoliad 2 yn gymwys mewn unrhyw achos pan fo hysbysiad adeiladu neu hysbysiad cychwynnol wedi ei roi i awdurdod lleol, neu pan fo planiau llawn wedi eu hadneuo gydag awdurdod lleol, cyn y diwrnod y daw’r Rheoliadau hyn i rym a phan fo’r gwaith adeiladu y mae’n ymwneud ag ef naill ai—
(a) wedi dechrau cyn y diwrnod hwnnw, neu
(b) yn dechrau o fewn y cyfnod o chwe mis sy’n dechrau â’r diwrnod hwnnw.
(2) Yn y rheoliad hwn—
 mae i “awdurdod lleol” yr ystyr a roddir i “local authority” gan adran 126 o Ddeddf Adeiladu 1984;
 mae i “cynlluniau llawn”, “gwaith adeiladu”, “hysbysiad adeiladu” a “hysbysiad cychwynnol” yr ystyron a roddir i “full plans”, “building work”, “building notice” ac “initial notice”, yn eu trefn, gan reoliad 2(1) o Reoliadau Adeiladu 2010.
Rebecca Evans
Ysgrifennydd y Cabinet dros yr Economi, Ynni a Chynllunio, un o Weinidogion Cymru
17 Mehefin 2025